Add colors to time slots

[tonyroberts]

Checklist

• [X] I checked for similar existing requests (both open and closed) before posting.
• [X] My request is generic, other users may benefit from it too.
• [X] I will participate in further discussion about this feature and can test it (if requested) once it's done.

Proposal

Related to #748

Making it possible to configure colors of the timeslots would make it easier to see what's scheduled at a glance, for example

Different use cases will require different color schemes (e.g. presets or fixed temperatures) and so the solution needs to be flexible, allowing the user complete control over the style used for each timeslot.

I suggest adding an optional javascript function to the config which if present will be called for each timeslot object and will return any additional style (background, color, etc) to apply to the timeslot.

Additional info

I've already implemented this in my own fork and will raise a PR for review shortly.

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 7 days

[tonyroberts]

@nielsfaber did you want to take a look at the PR for this? I don't have permission to remove the stale label, but the PR is ready to be merged. Thanks!

[github-actions[bot]]

This issue is stale because it has been open 30 days with no activity. Remove stale label or comment or this will be closed in 7 days