Update github templates

* release-v1.0.0:
  Update changelog to better expain password reset change (#5545)

Updates the v1.0.0 changelog to provide more information to those upgrading to v1.0 on why they may receive errors or find their password reset abilities have now been disabled.

Helps address #5444

because this file is reproduced on dockerhub and relative paths don't work

Change password reset links to /_matrix.

Add FAQ questions to federate.md. Add a health warning making it clear that the 1711 upgrade FAQ is now out of date.

Fix bug sending federation transactions with lots of EDUs

Share an SSL context object between SSL connections

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

If we try and send a transaction with lots of EDUs and we run out of
space, we call get_new_device_msgs_for_remote with a limit of 0, which
then failed.

Add some tests for bad certificates for federation and .well-known connections

turns out we need a shiny version of service_identity to enforce this
correctly.

Some keys are stored in the synapse database with a null valid_until_ms
which caused an exception to be thrown when using that key. We fix this
by treating nulls as zeroes, i.e. they keys will match verification
requests with a minimum_valid_until_ms of zero (i.e. don't validate ts)
but will not match requests with a non-zero minimum_valid_until_ms.

Fixes #5391.

It's not really a problem to trust notary responses signed by the old key so
long as we are also doing TLS validation.

This commit adds a check to the config parsing code at startup to check that
we do not have the insecure matrix.org key without tls validation, and refuses
to start without it.

This allows us to remove the rather alarming-looking warning which happens at
runtime.

This involves changing how the info callbacks work.

Sometimes the build agents get lost or die (error codes -1 and 2). Retry automatically a maximum of 2 times if this happens.

Error code reference:

* -1: Agent was lost
* 0: Build successful
* 1: There was an error in your code
* 2: The build stopped abruptly
* 255: The build was cancelled

fixes #5153 

Set default room version to v4.

Make a full SQL schema