Generate configuration documentation

[Yaraslaut]

trafficstars

It is often quite easy to forget about documentation entry on the web-page when adding new entry to the configuration. Some parts of the web-page are generated using contour executable already, for example info about supported VT sequences (https://contour-terminal.org/vt-sequence/) and key mapping section (https://contour-terminal.org/configuration/key-mapping/) It would be great to provide automatic generation of config entries for the web-page