New REST-like admin API

[sandhose]

MAS provides a new REST-like admin API

• Bootstrap a new REST-like admin API #2993
• Host a Swagger UI both in the static documentation and by the server #3018
• Add admin API to create users #3019
• Set password admin API #3021
• Lock user admin API #3022
• Unlock user admin API #3023
• Deactivate user admin API #3030
• Document the admin API #3038
• OAuth 2.0 sessions list and get admin APIs #3031
• Admin API to list OAuth 2.0/compat/browser sessions
• Admin API to finish sessions
• Admin API to create arbitrary OAuth 2.0 sessions
• Admin API to manage user emails

[matrixbot]

For your information, this issue has been copied over to the Element fork of matrix-authentication-service: element-hq/matrix-authentication-service#3057