v1.7.0-ls37

LinuxServer Changes:

Rebasing to alpine 3.12.
syncthing Changes:

v1.7.0

This release performs a database migration to optimize for clusters with
many devices.

Bugfixes:

• #6552: panic: Stop called more than once on ... created by nat.Service
• #6564: Closing an already removed connection causes GUI error message
• #6646: Misleading error message when to be deleted dir contains receive-only changes
• #6653: panic: nil pointer dereference in leveldb.(*DB).isClosed()
• #6654: panic: runtime error: index out of range in processNeeded()
• #6655: panic: nil pointer dereference in checkUpgrade()
• #6679: QUIC listener is not added when default TCP port is unavailable
• #6697: Malformed listen address causes hang on startup
• #6706: Changing a folder in web UI removes introduced-by info

Enhancements:

• #1830: "Folder path missing" when folder path is a junction
• #4703: Suggest setting up auth on initial startup
• #5910: Add Badger database backend for testing and consideration
• #6372: Reduce database size by optimizing version list storage

Other issues:

• #6608: Data race in Windows fs watcher tests
• #6625: TestRequestRemoteRenameChanged is racy/flaky