Day / night mode

[dennisguse]

Slowly implementing day/night mode.

This will include:

• migration to app compat themes
• app-wide configuration settings (default: night)
• tinting all icons properly
• cleaning up themes (this will also fix that the color of the search icon is different)
• move to material design components: https://material.io/develop/android/components/text-fields
• make activity spinner look nice
• charts
• set day background for trackController (later)

This PR changes the UI just by theming for day/night mode.
From my perspective some things do not yet look as polished as they were others are better.
What I don't like yet is the spinner styling (e.g., activity selector), but it saves us a lot of headaches not styling it :)

Fixes #231.

PS: I just found out that I toggle day/night mode easily on my LineageOS phone ;)

[dennisguse]

@thrillfall What do you think?

[rgmf]

This works for me. I like it.

[pstorch]

Only a few minor remarks:
The font is bigger now in the track list activity, so 1 track item less fits on the screen. Too big I opinion.
And the start/stop buttons have black background in day mode (I see you want to do this later).
The exclamation mark icon when deleting a track is too light in day mode, I think.

[dennisguse]

Thanks for testing and the feedback.
Almost done.

About the start/stop background: also yes.
The icons have a transparent background and this looks awkward on a bright background.
And my color selection skills are basically zero, but I will try something less bright.
Suggestions welcome.

PS: The delete dialog background also does not fit to the dark style - it is too dark compared to the preference dialogs.
Don't yet why.

[dennisguse]

The AlertDialog needs to be Androidx - that fixes the dark background color styling.

[dennisguse]

@kylecorry31 This PR implements day/night mode for OpenTracks.
Technically Trail-Sense and OpenTracks will look very much alike as both apps use almost the default color codes :)
Major difference is that our orange is slightly different (FF8800 vs FF6D00), but Trail-Sense's orange (from my perspective) fits better to the day theme.
Long story short: do you have any trouble, if we use the same for day/night in OpenTracks?

[kylecorry31]

No problem at all!

[dennisguse]

@kylecorry31 I tested this some days ago and then the colorAccent does not fit anymore with the logo. So, I guess we need something in the middle.