These were never used, and poking arbitary data into objects from other
packages seems confusing at best.

Storing server keys hammered the database a bit. This replaces the
implementation which stored a single key, with one which can do many updates at
once.

I was staring at this function trying to figure out wtf it was actually
doing. This is (hopefully) a non-functional refactor which makes it a bit
clearer.

This reverts commit c31e375a.

requests 2.22.0 as been released supporting urllib3 1.25.2

Signed-off-by: Marcus Hoffmann <bubu@bubu1.eu>

* expose SlavedProfileStore to ClientReaderSlavedStore

Add missing backslash

Only count aggregations from distinct senders

Block attempts to annotate the same event twice

Implements https://github.com/matrix-org/matrix-doc/pull/2002.

When considering the candidates to be forward-extremities, we must exclude soft
failures.

Hopefully fixes #5090.

* Pin eliot to <1.8 on python 3.5.2

Fixes https://github.com/matrix-org/synapse/issues/5199

* Add support for 'markers' to python_dependencies

* tell xargs not to strip quotes

Add startup background job for account validity

If we remove support for a particular room version, we should behave more
gracefully. This should make client requests fail with a 400 rather than a 500,
and will ignore individiual PDUs in a federation transaction, rather than the
whole transaction.

This reverts commit ce5bcefc.

This caused:

```
Traceback (most recent call last):
  File "/usr/local/lib/python3.7/runpy.py", line 193, in _run_module_as_main
    "__main__", mod_spec)
  File "/usr/local/lib/python3.7/runpy.py", line 85, in _run_code
    exec(code, run_globals)
  File "/home/synapse/src/synapse/app/client_reader.py", line 32, in <module>
    from synapse.replication.slave.storage import SlavedProfileStore
ImportError: cannot import name 'SlavedProfileStore' from 'synapse.replication.slave.storage' (/home/synapse/src/synapse/replication/slave/storage/__init__.py)
error starting synapse.app.client_reader('/home/synapse/config/workers/client_reader.yaml') (exit code: 1); see above for logs
```

Implements MSC1884

Rename relation types to match MSC

Land basic reaction and edit support.

Correctly update aggregation counts after redaction