Add FAQ section

[andig]

We have "Tips&FAQ" but it does not contain an FAQ:

• make FAQ a top level element
• rework tips section- its unclear what the sub pages refer to

FAQ topics:

• where is my sponsor token (use sponsor.evcc.io to retrieve it)
• what can I do about i/o timeout (check network and ensure only single client is accessing target device)
• why are my issues being closed without comment (complete full issue form, run on supported platform)
• why do I get invalid vehicle type: tesla-command (use official binaries)
• why does SolarEdge battery return weird numbers (known bug, ask SE to fix it- SolarEdge weird numbers one of the batteries evcc#12070)
• how can I diagnose why and where evcc is stuck- Fahrzeug wird nicht mehr erkannt evcc#12093 (comment)
• when does feature xyz appear/ when does the next release appear: when merged in nightly, released when release ready
• vehicle is offline: schauen ob Login auf Webseite/App möglich und/oder neue Terms&Conditions zu akzeptieren sind. Vor Ticketeröffnung über mehrere Tage/Neustarts nachverfolgen
• diagnose a frozen application: evcc "friert" förmlich ein evcc#12700 (comment)

[andig]

Fahrzeug kann nicht angelegt werden:

[main  ] ERROR 2024/06/28 15:25:03 creating vehicle Cupra failed: cannot create vehicle type 'template': cannot create vehicle type 'cupra': missing id_token
.Soc:     vehicle not available: cannot create vehicle type 'template': cannot create vehicle type 'cupra': missing id_token