[files_external] fix empty user mounts setting

Drop unused table file_map

Drop unused tables principalgroups and principals

* was removed in 3e84f170

* used only for windows support
* windows support was dropped in 8.2.0 - see #17379
* was introduced in fd8cb997
* ref #18935

Add coverity badge

Don't lock if we're only reading cache metadata

Coverity now scans our JS code…

adjust comment, this parameter was added for 9.0

* fixes #19858
* if no backend is allowed to be mounted also the user mount setting should be disabled

improve calculation of share recipients

add port to host only, if an URL is used instead of a plain hostname

Fix typo in variable name

Global classes in core CSS

Fix everyone count for subadmins

Correct the description of function setEncryptHomeStorage

* introduced with #20135 - c6f6a875

Fixes following error meessage:

{"reqId":"GliKwPFSIVn8GC2KNIHY","remoteAddr":"::1","app":"PHP","message":"Undefined variable: subAdmins at master\/settings\/users.php#76","level":0,"time":"2015-11-04T08:38:53+00:00","method":"GET","url":"\/master\/index.php\/settings\/users"}
{"reqId":"GliKwPFSIVn8GC2KNIHY","remoteAddr":"::1","app":"PHP","message":"Invalid argument supplied for foreach() at master\/settings\/users.php#76","level":0,"time":"2015-11-04T08:38:53+00:00","method":"GET","url":"\/master\/index.php\/settings\/users"}

Add a new core capability which tells the clients which url to use

Fix TagList namespace in property map

Apply new checkbox style in app settings

fix external storage wording detail, ref #19858

Don't validate searchbox