Calendar Api Feed Source

[tuj]

Link to ticket

https://leantime.itkdev.dk/#/tickets/showTicket/2321

Description

• Adds a new feed source for 'calendar' data, that depends on three API endpoints: locations, resources, events.
• Fixed multiselect when more than one feed source of the given type is installed.

Depends on: os2display/display-admin-client#264

Checklist

• My code is covered by test cases.
• My code passes our test (all our tests).
• My code passes our static analysis suite.
• My code passes our continuous integration process.

TODOs

• Configurable date format for startTime and endTime.
• Better cache handling.
• Configurable caching lifetimes.
• Tests.
• Enviroment variables in infrastructure.
• Filter resources by locations in feed source.
• Set locations in feed source from api endpoint