Port/Rewrite Plan

See merge request !10

Add new helper property to model
Add and use template tag for color coding
Add helpfer functions for color blending (gradient and simple)
Also show timestamp of last edit in admin view
Introduce setting to control which changes will be higlighted

Dashboard custom buttons

Closes #17

See merge request !9

Move encoding to own files that can be included
Add url for linking to detail page to event encoding
Add color coding for category and track to event encoding
Introduce room hierarchy (building + room)

Introduce common base template for plan views
Move breadcrumbs to own file for easy referencing
Load common fullcalendar base files in base template
Introduce new block for other fullcalendar operations

Adapt dashboard links to new URL structure of plan
Introduce conditional loading of paths to central URL file

Adapt filenames, references and URLs
Adapt settings keys
Adapt translations
Fix wrong settings keys in wall view

Add views
Add templates
Add urls
Add translations
Add three corresponding settings to central settings file
Minor: Fix typo in plan_akslot

Adapt admin views
Adapt rendering of times of AK slots for backend and frontend

Add dependency django-timezone-field
Add timezone field to Event
Introduce i18n for default_slot field
Add new and missing translations
Add title property to Room (for better access of combined building + name form)

fix typo

Introduce model
Introduce admin interface
Show buttons on dashboard start page

Add little space between the buttons

New features

See merge request kif/akplanning!8

deploy dashboard under /
create template view
provide template with important links for each event
handle case of no events
create template tag to ensure installed apps

maintaining naming convention