This release updates the CLI to use subcommands and adds the subcommands
`cli` (previously standalone `stcli` utility) and `decrypt` (for offline
verifying and decrypting encrypted folders).

With this release we invite everyone to test the "untrusted (encrypted)
devices" feature. You should not use it yet on important production
data. Thus UI controls are hidden behind a feature flag. For more
information, visit:
https://forum.syncthing.net/t/testing-untrusted-encrypted-devices/16470

Bugfixes:

- #7385: infinite filesystem recursion due to missing file id
- #7419: panic "Snapshot(): database is closed" on start after wiping database
- #7429: "Ignore Patterns" tab disappears after visiting "Folder Defaults"
- #7434: Non-DNS-like computer name fails creation of HTTPS certificate
- #7451: strelaysrv v1.14.0 failing to load
- #7466: Receive-encrypted fails after a while: file with empty block list
- #7469: .stignore should be ignored in Receive Encrypted folders
- #7474: Device tries to push ignored files to a remote device in a 3-device setup
- #7481: Versioning help strings are not displayed in the GUI

Enhancements:

- #6566: Ship stcli in main package
- #7457: Remove sub-second precision from the REST API rest/stats/device.

Other issues:

- #4719: Package stcli as Debian package
- #7199: Build script -no-upgrade handling is unintuitive