Mautrix

* Added `remote_id` field to `push_bridge_state` method.

* Added tests for `factory` and `hidden` serializable attrs.
* Added `login-matrix`, `logout-matrix`, `ping-matrix` and `clear-cache-matrix`
commands in the bridge module. To enable the commands, bridges must implement
the `User.get_puppet()` method to return the `Puppet` instance corresponding
to the user's remote ID.
* Fixed logging events that were ignored due to lack of permissions of the sender.
* Fixed deserializing encrypted edit events ([mautrix/telegram623]).

[mautrix/telegram623]: https://github.com/mautrix/telegram/issues/623

* Replaced `GenericSerializable` with a bound `TypeVar`.
* This means that classes extending `SerializableAttrs` no longer have to use
the `class Foo(SerializableAttrs['Foo'])` syntax to get type hints, just
`class Foo(SerializableAttrs)` is enough.
* Backwards compatibility for using the `['Foo']` syntax will be kept until v0.10.
* Added `field()` as a wrapper for `attr.ib()` that makes it easier to add
custom metadata for serializable attrs things.
* Added some tests for type utilities.
* Changed attribute used to exclude links from output in HTML parser.
* New attribute is `data-mautrix-exclude-plaintext` and works for basic
formatting (e.g. `<strong>`) in addition to `<a>`.
* The previous attribute wasn't actually checked correctly, so it never worked.

* Added `SynapseAdminPath` to build `/_synapse/admin` paths.

* Updated bridge status pushing utility to support `remote_id` and `remote_name`
fields to specify which account on the remote network is bridged.

* Switched to stable space prefixes.
* Added option to send arbitrary content with membership events.
* Added warning if media encryption dependencies aren't installed.
* Added support for pycryptodomex for media encryption.
* Added utilities for pushing bridge status to an arbitrary HTTP endpoint.