Add floor_entities function and filter

[Petro31]

Breaking change

Proposed change

Add floor_entities function & filter to templates to reduce templates like this:

{{['dorm','aanbouw','woongedeelte']|map('floor_areas')|sum(start=[])
            |map('area_entities')|sum(start=[])
            |select('in',label_entities('binnenlamp'))
            |select('is_state','on')|list|sort}}

to this

{{ floor_entities('begane_grond')
            |select('in',label_entities('binnenlamp'))
            |select('is_state','on')|list|sort}}

Relevant WTH -> here

Type of change

• Dependency upgrade
• Bugfix (non-breaking change which fixes an issue)
• New integration (thank you!)
• New feature (which adds functionality to an existing integration)
• Deprecation (breaking change to happen in the future)
• Breaking change (fix/feature causing existing functionality to break)
• Code quality improvements to existing code or addition of tests

Additional information

• This PR fixes or closes issue: fixes #
• This PR is related to issue:
• Link to documentation pull request: Add floor_entities function and filter home-assistant.io#37107

Checklist

• The code change is tested and works locally.
• Local tests pass. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.
• I have followed the development checklist
• I have followed the perfect PR recommendations
• The code has been formatted using Ruff (ruff format homeassistant tests)
• Tests have been added to verify that the new code works.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated for www.home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• The manifest file has all fields filled out correctly.
  Updated and included derived files by running: python3 -m script.hassfest.
• New or updated dependencies have been added to requirements_all.txt.
  Updated by running python3 -m script.gen_requirements_all.
• For the updated dependencies - a link to the changelog, or at minimum a diff between library versions is added to the PR description.

To help with the load of incoming pull requests:

• I have reviewed two other open pull requests in this repository.