Release 1.2.4

Release 1.2.4

* Implement new multipattern matcher that uses hyperscan if possible
* Use mutlipattern for lua_trie code
* Add utility methods for multipattern
* Use multipattern in url matcher
* Add escape functions for hyperscan
* Allow to optimize lua -> C transition by flattening table args
* Optimize hot paths in SA plugin
* Optimize rspamd_re_cache_type_from_string
* Allow empty tries
* Fix extraction of URLs from Subject
* Allow to have different flags for different patterns in multipattern
* Add common directory for hyperscan cache to config
* Implement caching for hyperscan multipattern
* Attach domain part to `R_SUSPICIOUS_URL` (by @moisseev)
* Allow multipattern scans to be nested for the case of hyperscan
* Simplify SURBL redirector search code and avoid ac_trie
* Add two way substring search algorithm
* Avoid acism usage to find gtube pattern
* Fix processing of empty headers
* Allow to disable pthread mutexes on broken platforms
* Make web interface not send password in query strings (#585) by @fatalbanana
* Add maximum delay to ratelimit module
* Backport fix for empty files inclusion from libucl
* Fix settings id setup
* Add min_learns option to classifiers
* Use more clever to utf8 conversion strategy
* Fix disabling of virtual symbols in the settings
* Rework settings to work properly in metric-less configuration
* Set the default limit for classifier
* Fix ttl based expiration from LRU cache
* Rework DKIM module to use OpenSSL for digests
* Fix mailto urls parsing with hyperscan
* Do not set obscured flag for urls starting with spaces
* Fix crash on redis learn
* Fix ratelimit ctime setting

Signed-off-by: Vsevolod Stakhov <vsevolod@highsecure.ru>