* This is an experimental implementation
* Added `www-data` feature and two new config options to clixon-config.yang:
* `CLICON_WWW_DATA_PATH`
* `CLICON_WWW_DATA_ROOT`
* The limited implemtation is as follows:
* path: Local files within `CLICON_WWW_DATA_ROOT`
* operation GET, HEAD, or OPTIONS
* query parameters not supported
* indata should be NULL (no write operations)
* Limited media: text/html, JavaScript, image, and css
* Authentication as restconf
Generic changes:
* Uniform path selection across fcgi, native http/1 + http/2
