Stop installing Matrix Console by default

[richvdh]

This is based on the work done by @krombel in #2601.

Fixes #1417, and kinda fixes #1527.

[codecov-io]

Codecov Report

Merging #4290 into develop will increase coverage by <.01%.
The diff coverage is 52.94%.

@@             Coverage Diff             @@
##           develop    #4290      +/-   ##
===========================================
+ Coverage    73.49%   73.49%   +<.01%     
===========================================
  Files          302      302              
  Lines        29892    29893       +1     
  Branches      4887     4892       +5     
===========================================
+ Hits         21968    21969       +1     
+ Misses        6488     6484       -4     
- Partials      1436     1440       +4

Impacted Files	Coverage Δ
synapse/python_dependencies.py	40.9% <ø> (ø)	⬆️
synapse/app/homeserver.py	57.52% <42.85%> (+0.66%)	⬆️
synapse/config/server.py	63.79% <60%> (-0.1%)	⬇️
synapse/util/file_consumer.py	80.7% <0%> (-1.76%)	⬇️
synapse/handlers/user_directory.py	70.73% <0%> (-0.31%)	⬇️

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