MatrixTransport.send_global method

[andrevmatos]

Method to send messages to one of the configured global rooms.
Needed for #3273 , based on top of #3427 so should be merged after it.

[codecov]

Codecov Report

❗ No coverage uploaded for pull request base (master@1d90895). Click here to learn what that means.
The diff coverage is 84.21%.

@@            Coverage Diff            @@
##             master    #3436   +/-   ##
=========================================
  Coverage          ?   76.03%           
=========================================
  Files             ?      100           
  Lines             ?    12973           
  Branches          ?     1825           
=========================================
  Hits              ?     9864           
  Misses            ?     2464           
  Partials          ?      645

Impacted Files	Coverage Δ
raiden/network/transport/matrix/__init__.py	100% <ø> (ø)
raiden/network/transport/udp/udp_transport.py	89.95% <50%> (ø)
raiden/network/transport/matrix/transport.py	75.16% <82.6%> (ø)
raiden/network/transport/matrix/utils.py	75.83% <87.5%> (ø)

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[codecov]

Codecov Report

Merging #3436 into master will increase coverage by 0.05%.
The diff coverage is 92.3%.

@@            Coverage Diff             @@
##           master    #3436      +/-   ##
==========================================
+ Coverage   76.22%   76.27%   +0.05%     
==========================================
  Files         101      101              
  Lines       13129    13142      +13     
  Branches     1837     1838       +1     
==========================================
+ Hits        10007    10024      +17     
- Misses       2469     2470       +1     
+ Partials      653      648       -5

Impacted Files	Coverage Δ
raiden/network/transport/matrix/transport.py	75.48% <100%> (+1.74%)	⬆️
raiden/network/transport/udp/udp_transport.py	89.95% <50%> (-1.14%)	⬇️
raiden/utils/__init__.py	67.44% <0%> (-4.66%)	⬇️
raiden/network/proxies/token_network.py	80.76% <0%> (-0.64%)	⬇️
raiden/messages.py	88.74% <0%> (-0.17%)	⬇️
raiden/transfer/events.py	74% <0%> (+0.4%)	⬆️
raiden/tasks.py	74.8% <0%> (+0.78%)	⬆️
raiden/transfer/mediated_transfer/events.py	84.11% <0%> (+0.93%)	⬆️
... and 1 more

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[rakanalh]

Also looks good with some minor comments.

I am also missing where the integration between the new monitoring-specific messages and send_global is done. I am assuming that's going to be in a follow up PR, right?

[ulope]

Two nitpicks. Otherwise LGTM.