Feat/161

[cpvalente]

This should offer an MVP for showing times in 12 hour format.
The user can decide this in the settings menu via the dropdown or override locally in the viewers by adding format=12 or format=24 to the URL parameters

time entry and in app times are all in 24 hours. will not redesign since the components are under review with #55

[alexrohleder]

In general, I think we should aim in having a smaller centralized solution for this problem. It seems we're solving it multiple times across the app. We can discuss ways of doing that, please let me know if you have any doubt.

[cpvalente]

Hey Alex, really good input here.
I have made some changes to the state and centralised the time formatting.

The PR is becoming pretty big so I believe its best to leave some of the refactorings for separate PRs.
For now I will create branches for refactoring forms, we will get to the rest eventually

Either way, it would be great to have some feedback on the work here. Thank you again, good stuff