Migration to VueJs and more

[Sebclem]

I'm currently migrating the addon to VueJs + Typescript, this will make the app more easy to maintain and i'm also planning to add some unit/e2e test.

With this migration I will also implement some long wanted features.
This issue is here to track my progress.

Features:

• Multiple cron Multiple backups - daily, weekly, monthly, yearly #88
• Chunked upload (This will prevent 413 errors Fail to upload snapshot to nextcloud (Status code: 413) ! #9)
• Home assistant status entity Add notification support #1
• Partial / Full backup support Snapshots always listed as partial ! #63
• Custom Webdav endpoint Can u support plain webdav? #108 Upload to owncloud fails (or: Please support owncloud) #89
• Auto empty trashbin Automatic clean the trashbin at nextcloud  #103
• Rebuild status
• Tests

UI:

• Event viewer
• Status viewer
• Cloud config
• Backup config
• Backup viewer HA
• Backup viewer Cloud

Bug:

• Invalid password cause brute force security to trigger (webdav)
• Performance issue when message list is getting big