docs: rename and reorganize documentation files

[derpierre65]

this is the first step of the docs update

• removed unused config.adoc file and moved the content to the real config.adoc file
• fixed issues on the config page
• add warning to icons, that the icons will not generated on a dedicated server
• moved groups to read category, it's better to have a group of read and write endpoints, in the next steps i want to group the endpoints more
• read/write index page has now a table with all available endpoints, for an easy search with the link to the page and a short description
• warning for webhooks/websocket feature, that this is not yet re-implemented
• removed old setCircuit docs, and will be re-implemented soon (as endpoint and docs)
• new getSpaceElevator & getFactory view (i moved some rows into separate files to re-use them)

i will update the endpoints itself in the next pr(s)

i am absolutley not sure if everything is correct, i have never worked with adoc files before

here is an example from my editor of what the page should look like