add indie.json for Indie App Store listing

Return 503 in  public.php and OCS API when upgrade is due

change 'Cancel upload' text to x icon for more space in breadcrumbs bar

Use filtered list for ext storage list mounts API

Use get random bytes as uniqeid() is not unique in some cases

Fixes typo with sendmail detection - fixes #9203

[encryption] check if file still exists before removing encryption keys

Design share fixes

To prevent unexpected behavior, public.php and the OCS API calls will
return 503 Service Unavailable when an upgrade is due.

Do not strict compare item source id so the dropdown is closed correctly

[server2server-sharing] no longer check if the external storage app is enabled

Fix #8841

no longer check if the external storage app is enabled, we use no the webdav implementation from core

Now the external storage correctly returns the mount points visible only
for the current user by using the method getAbsoluteMountPoints() which
is already filtered.

Since that call was missing the backend name which is important for the
UI, this one was added as well.

Fix test mail behaviour

Fix #9161

always regenerate etag when writing back file to objectstore

shorten userid columns to 64 chars, ref #9186

more strings to translate in utils also some fixes in defaults

fix server share dialog title

fix trailing whitespace noted by Scrutinizer

some strings to localize external mount api responses. fix #8094

Use file_source to find matching share for nested link shares

delete operation