Sync with Collabora fork

[andrewshadura]

Similarly to #160, we’d like to get rid of our custom fork and have as much of our changes as possible in the upstream gTimeLog. Our fork lives at our Gitlab instance.

We ourselves made multiple attempts at refining and rebasing our changes, e.g. this, this one, or this one.

The three main features we need are:

• Timezone support (Timezones #84)
  • We attacked it differently, by extending the format to add an extra field, e.g.: 2018-06-22 09:00 +0200: ** morning
• Ability to get the task list from Chronophage, our time tracking solution
  • This feature is roughly a match to the feature already present in gTimeLog, but in our fork it allows for hierarchy of tasks (e.g. customer: project: task-type: task: …)
• Ability to upload to Chronophage
  • It’s basically a POST request at a URL IIRC

I’ll add more things later

[gebi]

yea, the hierarchy of tasks would be AWESOME!
we'd need that too.