Disable JOSM styles report.
Remove temporary hack.
Preparations to remove JOSM source.

* in_josm will now always be 0.
* Whether a key is in the JOSM config or not will not influence
  standing in tag cloud on main page any more.
Remove in_josm usages in reports.
Remove wiki column in report "Wiki pages about non-existing keys".

This is always set by definition so no reason to show it.
More JOSM cleanup.
Prepare for putting project stats in db.keys and db.values.
Do not show in_josm column any more in keys view.
Always return false for in_josm in api/v4/keys and document that.