v1.4.0-rc.10

This is a release candidate for the v1.4.0 minor release.

Important changes:

- A new config option maxConcurrentIncomingRequestKiB has been added to
  limit the maximum amount of request data being concurrently processed
  due to incoming requests. This limits Syncthing's peak RAM usage when
  there are many connected devices all requesting file data. The default
  is 256 MiB.

- The config option maxConcurrentScans has been removed and replaced a
  new config option maxFolderConcurrency. In addition to just limiting
  concurrent scans it now also limits concurrent sync operations. The
  default is the number of available CPU threads ("GOMAXPROCS").

- Syncthing now always runs the monitor process, which previously was
  disabled with -no-restart. This facilitates crash reporting and makes
  logging behave more consistently. The observed behavior with
  -no-restart should be the same as before but the internals differ.

- The database schema has been improved and will result in a migration
  plus compaction at first startup after the upgrade.

Bugfixes:

- #4774: Doesn't react to Ctrl-C when run in a subshell with -no-restart (Linux)
- #5952: panic: Should never get a deleted file as needed when we don't have it
- #6281: Progress emitter uses 100% CPU
- #6300: lib/ignore: panic: runtime error: index out of range [0] with length 0
- #6304: Syncing issues, database missing sequence entries
- #6335: Crash or hard shutdown can case database inconsistency, out of sync

Enhancements:

- #5786: Consider always running the monitor process
- #5898: Database performance: reduce duplication
- #5914: Limit folder concurrency to improve performance
- #6302: Avoid thundering herd issue by global request limiter
-----BEGIN PGP SIGNATURE-----
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=mTh5
-----END PGP SIGNATURE-----