Refactor MatrixFederationAgent to retry SRV.

* Allow schema deltas to be engine-specific

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>

* Newsfile

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>

* Code style (Black)

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>

Increase profile display name limit

Add config option to sign remote key query responses with a separate key.

public_base_url is actually public_baseurl

Admin API: Set adminship of a user

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>

Signed-off-by: Olivier Wilkinson (reivilibre) <olivier@librepush.net>

Signed-off-by: Aaron Raimist <aaron@raim.ist>

Signed-off-by: Aaron Raimist <aaron@raim.ist>

Propagate opentracing contexts through EDUs
Co-Authored-By: Richard van der Hoff <1389908+richvdh@users.noreply.github.com>

Remove shared secret registration

Propagate opentracing contexts across workers


Also includes some Convenience modifications to opentracing for servlets, notably:
- Add boolean to skip the whitelisting check on inject
  extract methods. - useful when injecting into carriers
  locally. Otherwise we'd always have to include our
  own servername and whitelist our servername
- start_active_span_from_request instead of header
- Add boolean to decide whether to extract context
  from a request to a servlet

This type of registration was probably never used. It only includes the
user name in the HMAC but not the password.

Shared secret registration is still available via
client/r0/admin/register.

Signed-off-by: Manuel Stahl <manuel.stahl@awesome-technologies.de>

This reverts commit 27a686e5.

This reverts commit 3320aaab.

Retry well known on fail

Add opentracing tags and logs for e2e keys

There's no point doing a raise_from here, because the exception is always
logged at warn with no stacktrace in the caller. Instead, let's try to give
better messages to reduce confusion.

In particular, this means that we won't log 'Failed to connect to remote
server' when we don't even attempt to connect to the remote server due to
blacklisting.

These tables are never used, so we may as well drop them.

This allows servers to separate keys that are used to sign remote keys
when acting as a notary server.

Get rid of the labyrinthine `recoverer_fn` code, and clean up the startup code
(it seemed to be previously inexplicably split between
`ApplicationServiceScheduler.start` and `_Recoverer.start`).

Add some docstrings too.

Hopefully, this will fix a stack overflow when recovering an appservice.

The recursion here leads to a huge chain of deferred callbacks, which then
overflows the stack when the chain completes. `inlineCallbacks` makes a better
job of this if we use iteration instead.

Clean up the code a bit too, while we're there.

Update opentracing docs to use the unified 'trace' method