feat: carddav client

[asbiin]

This depends on #3749
It will close #2738

This adds the ability to add an external carddav source, and sync contacts in a new address book.
There are 2 steps

• Add a new address book: this is currently done with a new Command monica:newaddressbooksubscription. A dedicated UI will be added later in another PR.
• Sync the contacts: this is done by a new schedule command, based on a frequency

Limitations

• Second address book is not displayed in Monica today. This has to be done in another PR
• The external carddav server must respect standards.
  For instance, this is not the case of google api... Hopefully I managed how to handle this specific case, but we will not add further exceptions.
• When adding multiple address books (Monica comes with at least 1 default address book per account), there is no way to "merge" duplicates (= same contact in different address books). This has to be done in another PR
• There is no way to handle errors: if an address book sync has an error, it's logged in the app logs, but this it not accessible by the user, and new sync will be triggered again and again.

[sonarcloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
2 Code Smells

87.8% Coverage
0.0% Duplication

[cstrat]

Do you know if this update will address #5150 ??

Sorry I just realised this is to add a carddav client to Monica, thats cool!
Probably doesn't update the carddav server which is serving contacts out right?

[github-actions]

🎉 This PR is included in version 3.3.0 🎉

The release is available on:

• GitHub release
• v3.3.0

Your semantic-release bot 📦🚀

[sitarane]

Hey, sorry to reanimate this thread, but I've been trying to figure out how to use this feature for a few days and I can't get my head around it.
If I understand well, this merged PR means that Monica can now get contacts from a third party CardDAV server, my usecase would be Nextcloud.
How do I point Monica to a CardDAV server?

[daniele-athome]

I can't find any documentation about it, but a user tried: #5654

[daniele-athome]

By the way is the synchronization one-way? Meaning CalDAV data is only read from the server, right?

[cstrat]

I am finding strange behaviour where my Monica contacts on my iPhone over time simply duplicate themselves.
I need to disconnect Monica from my Contacts, let it purge my contact list, then re-enable it and sync again.

[github-actions]

This pull request has been automatically locked since there
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Please open a new issue for related bugs.