Release 1.7.3

Release 1.7.3

* [CritFix] Plug bad memory leak in protocol reply
* [Feature] Add avx2 codec for base64
* [Feature] Add method to receive all URL flags from Lua API
* [Feature] Allow to fold headers on stop characters
* [Feature] Allow to set lua_cpath from options
* [Feature] Allow to specify custom rejection message in milter
* [Feature] Deal with unnormalised Unicode obfuscation
* [Feature] Do not detect language twice for relative parts
* [Feature] Implement oversigning feature
* [Feature] Implement silent logging level to minimize noise in logs
* [Feature] Improve URL_IN_SUBJECT rule
* [Feature] Use hashing to reduce redis attack surface
* [Fix] Add oversigning for the most important headers
* [Fix] add 'rewrite subject' to History dropdown
* [Fix] Another fix in folding algorithm
* [Fix] Do not call multimap addr for parts of addr if filter is presented
* [Fix] Do not clean hostname on generic reset
* [Fix] Do not create pid file in no-fork mode
* [Fix] Fix fold_after case to preserve multiple spaces
* [Fix] Fix folding and folding tests
* [Fix] Fix hostname usage in milter mode
* [Fix] Fix lua RSA verify and its tests
* [Fix] Fix metadata exporter send_mail backend (#2124)
* [Fix] Fix processing of '\v' in libucl
* [Fix] Fix shemaless URLs detection
* [Fix] Fix support of multiple headers in sign_header
* [Fix] Fix usage of util.parse_mail_address
* [Fix] Fix weights of dynamic squeezed rules
* [Fix] Leak from bucket before checking the burst
* [Fix] Stop using own localtime as DST could be messy in many cases
* [Fix] Treat unnormalised URLs as obscured
* [Rework] Restore leaky bucket model in ratelimit plugin
* [WebUI] Add messages total to throughput summary
* [WebUI] Add symbols order selector to history
* [WebUI] Config: Load list on demand
* [WebUI] Fix modalBody for maps that appear more than once
* [WebUI] History: Fix Tooltips on paging, filtering and sorting
* [WebUI] Remove a previously-attached event handler
* [WebUI] Update D3 to v5.0.0 and jQuery to v3.3.1

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