Move raw API and event schemas into /data directory

Historical note: this was originally a series of several commits, spread out
over several weeks. They have been squashed together to make `git annotate`
work properly.

The original commits were:
 * 91ab3934 <Will> 2021-01-25 21:16:42 -0800 Add raw API end event schemas into /data directory
 * aae22f47 <Will> 2021-01-25 21:33:06 -0800 Remove non-data files
 * 1092d4ca <Will> 2021-01-26 20:41:33 -0800 Add data-compatiuble extension (.yaml) to all data files that currently omit one
 * 21060109 <Will> 2021-01-26 20:57:28 -0800 Remove symlink to event-schemas, and update openAPI schema paths accordingly
 * 4f633845 <Travis Ralston> 2021-04-12 21:54:54 -0600 Fix event schema examples too
 * 301c7b2f <Will> 2021-02-05 10:15:42 -0800 Restore docs describing OpenAPI extensions that we use

data/api/client-server/inviting.yaml

@@ -0,0 +1,123 @@
+# Copyright 2016 OpenMarket Ltd
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+swagger: '2.0'
+info:
+  title: "Matrix Client-Server Room Joining API"
+  version: "1.0.0"
+host: localhost:8008
+schemes:
+  - https
+  - http
+basePath: /_matrix/client/%CLIENT_MAJOR_VERSION%
+consumes:
+  - application/json
+produces:
+  - application/json
+securityDefinitions:
+  $ref: definitions/security.yaml
+paths:
+  # With an extra " " to disambiguate from the 3pid invite endpoint
+  # The extra space makes it sort first for what I'm sure is a good reason.
+  "/rooms/{roomId}/invite ":
+    post:
+      summary: Invite a user to participate in a particular room.
+      description: |-
+        .. _invite-by-user-id-endpoint:
+
+        *Note that there are two forms of this API, which are documented separately.
+        This version of the API requires that the inviter knows the Matrix
+        identifier of the invitee. The other is documented in the*
+        `third party invites section`_.
+
+        This API invites a user to participate in a particular room.
+        They do not start participating in the room until they actually join the
+        room.
+
+        Only users currently in a particular room can invite other users to
+        join that room.
+
+        If the user was invited to the room, the homeserver will append a
+        ``m.room.member`` event to the room.
+
+        .. _third party invites section: `invite-by-third-party-id-endpoint`_
+      operationId: inviteUser
+      security:
+        - accessToken: []
+      parameters:
+        - in: path
+          type: string
+          name: roomId
+          description: The room identifier (not alias) to which to invite the user.
+          required: true
+          x-example: "!d41d8cd:matrix.org"
+        - in: body
+          name: body
+          required: true
+          schema:
+            type: object
+            example: {
+              "user_id": "@cheeky_monkey:matrix.org",
+              "reason": "Welcome to the team!"
+            }
+            properties:
+              user_id:
+                type: string
+                description: The fully qualified user ID of the invitee.
+              reason:
+                type: string
+                description: |-
+                  Optional reason to be included as the ``reason`` on the subsequent
+                  membership event.
+            required: ["user_id"]
+      responses:
+        200:
+          description: The user has been invited to join the room.
+          examples:
+            application/json: {
+              }
+          schema:
+            type: object
+        400:
+          description: |-
+
+            The request is invalid. A meaningful ``errcode`` and description
+            error text will be returned. Example reasons for rejection include:
+
+            - The request body is malformed (``errcode`` set to ``M_BAD_JSON``
+              or ``M_NOT_JSON``).
+
+            - One or more users being invited to the room are residents of a
+              homeserver which does not support the requested room version. The
+              ``errcode`` will be ``M_UNSUPPORTED_ROOM_VERSION`` in these cases.
+          schema:
+            "$ref": "definitions/errors/error.yaml"
+        403:
+          description: |-
+            You do not have permission to invite the user to the room. A meaningful ``errcode`` and description error text will be returned. Example reasons for rejections are:
+
+            - The invitee has been banned from the room.
+            - The invitee is already a member of the room.
+            - The inviter is not currently in the room.
+            - The inviter's power level is insufficient to invite users to the room.
+          examples:
+            application/json: {
+              "errcode": "M_FORBIDDEN", "error": "@cheeky_monkey:matrix.org is banned from the room"}
+          schema:
+            "$ref": "definitions/errors/error.yaml"
+        429:
+          description: This request was rate-limited.
+          schema:
+            "$ref": "definitions/errors/rate_limited.yaml"
+      tags:
+        - Room membership