Log Message:
mail/rspamd: Update to 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