* lib/httpserver: added tlsCipherSuites flag
* lib/httpserver: compare lower case strings
* lib/httpserver: use EqualFold
* lib/httpserver: used flagutil.NewArray, supported only strings cipher suites
* lib/httpserver: updated flag description, added flag to documentation
* Update lib/httpserver/httpserver.go
Co-authored-by: Aliaksandr Valialkin <valyala@victoriametrics.com>
