Allows a scene to trigger another scene

[rob-mccann]

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Description of change

This change adds an action to scenes which triggers another scene.

A few assumptions have been made here which I'd be happy to revisit based on feedback:

• There's no validation that a scene exists in the backend
• A scene can only trigger another scene once across all action groups
  • In the cyclical scenario (for example, Scene A that triggers Scene B that triggers Scene A), each scene will be called once only and a warning message logged. This is handled at execution time by remembers which scenes were already called.
  • There's no cyclical checks/validation done when a scene is created at the moment; I suggest this is handled in a separate PR to make this easier to review and in the interest of making it incrementally better :)
• At the moment, there isnt trigger shown in the scene being called

If you're happy with the approach, I'll go ahead and update the docs.

Closes #797

[codecov]

Codecov Report

Merging #1124 (801d3ba) into master (c9e764a) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #1124   +/-   ##
=======================================
  Coverage   96.45%   96.45%           
=======================================
  Files         644      644           
  Lines        8200     8205    +5     
=======================================
+ Hits         7909     7914    +5     
  Misses        291      291           

Impacted Files	Coverage Δ
server/models/scene.js	93.75% <ø> (ø)
server/lib/scene/scene.actions.js	97.41% <100.00%> (+0.06%)	⬆️
server/lib/scene/scene.execute.js	100.00% <100.00%> (ø)

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[atrovato]

Tested locally, looks fine.
2 things:

• we may want to add a message in the UI to tell the user that scenes won't loop
• execution conditions of the child scene are ignored (to execute it), maybe the user needs to know it too

what about a ℹ️ tooltip on scene selection box?

[Pierre-Gilles]

When I click on the start scene button:

I got this error:

I guess it's because alreadyExecutedScenes does not exist at this stage

[Pierre-Gilles]

Looks good to me this time! Thanks for the PR, great work 🙏