Hide ciphers from non-selected collections for org owners/admins

Fixing MsgPack headers type and support mobile SignalR

If org owners/admins set their org access to only include selected
collections, then ciphers from non-selected collections shouldn't
appear in "My Vault". This matches the upstream behavior.

Clarify multiuser capabilities

Fix the Alpine build

Delete associated favorites when deleting a cipher or user

This prevents foreign key constraint violations.

Diesel requires the following changes:
- Separate connection and pool types per connection, the generate_connections! macro generates an enum with a variant per db type
- Separate migrations and schemas, these were always imported as one type depending on db feature, now they are all imported under different module names
- Separate model objects per connection, the db_object! macro generates one object for each connection with the diesel macros, a generic object, and methods to convert between the connection-specific and the generic ones
- Separate connection queries, the db_run! macro allows writing only one that gets compiled for all databases or multiple ones

Track favorites on a per-user basis

Add more docs on the `email_token_size` setting

Sync global_domains.json with upstream

Generate tokens more simply and uniformly

Currently, favorites are tracked at the cipher level. For org-owned ciphers,
this means that if one user sets it as a favorite, it automatically becomes a
favorite for all other users that the cipher has been shared with.

In particular, Diesel aliases `Varchar` to `Text`, and `Blob` to `Binary`:

* https://docs.diesel.rs/diesel/sql_types/struct.Text.html
* https://docs.diesel.rs/diesel/sql_types/struct.Binary.html

Add more doc comments for MySQL/PostgreSQL connection URIs

Sync global_domains.json to bitwarden/server@61b11e3

Add a note that settings in .env can be overridden

Note that Diesel implements its own parser for MySQL connection URIs, so it
probably doesn't accept the full range of syntax that would be accepted by
MySQL's client libraries, whereas for PostgreSQL, Diesel simply passes the
connection string/URI to PostgreSQL's libpq for processing.

Make the admin URL redirect try to use the referrer first, and use /admin when DOMAIN is not configured and the referrer check doesn't work, to allow users without DOMAIN configured to use the admin page correctly