Expose camera PTZ information over websocket

[dermotduffy]

• For Transparently call Frigate PTZ via integration dermotduffy/frigate-hass-card#1163 .

[dermotduffy]

@NickM-27 Would appreciate your thoughts on this, in general, but specifically:

• This is relying on the ptz/info API call that I randomly found :-) Let me know if this is not going to stick around!
• I am making the choice to expose this over websocket, even though the API call is over raw http. In general, unless we think something will be used by lots of people (i.e. not this!), I think it's better to "pollute" the websocket space than the "HTTP View" space, which would expose the endpoint more publicly.

PS: Build failure seems to be something unrelated, saw this in another PR, will investigate separately.

[NickM-27]

1. That'll be sticking around, it is used not only in the frigate webui but also for ptz auto tracking
2. I don't see any issues with that 👍

[codecov]

Codecov Report

All modified lines are covered by tests ✅

Comparison is base (a31922f) 100.00% compared to head (b3c9cde) 100.00%.
Report is 5 commits behind head on dev.

Additional details and impacted files

@@            Coverage Diff            @@
##               dev      #556   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files           15        15           
  Lines         1963      1978   +15     
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+ Hits          1963      1978   +15     

Files	Coverage Δ
custom_components/frigate/api.py	100.00% <100.00%> (ø)
custom_components/frigate/ws_api.py	100.00% <100.00%> (ø)

... and 3 files with indirect coverage changes

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