Plugins may want to add further fields to be present when saving drafts

This is useful for plugins that want to replace the default editor and
use their own editor instead and need to do some work before their output
can be saved as syntax.

introduce INFO_DEPRECATION_LOG event

now the method is aborting early again unless the data is actually used

Sometimes, preparing the data for an event is expensive and only needed
if the event is actually handled. This allows for a quick check before
actually preparing and triggering the event.

This adds an event to dbg_deprecated(). This allows plugins to handle
deprecation warnings. One example would be @cosmocode/dokuwiki-plugin-sentry

One thing I don't like, but don't know how to avaoid is that this
function used to abort super early when $conf['allowdebug'] wasn't set.

However for the sentry plugin you probably would want logs, but still do
not show any debugging to end users (which allow debug would do).

So now the backtrace is always built, the event triggered and then
everything is sent to dbglog() which may simply throw everything away.

Suggestions on how to improve this welcome.

Add call to delete Users to the remote API

These shouldn't be there anymore since the plugins have been deleted

Translation update (de)

PHP brekas URLs by moving old releases into an archive folder. Since we
cannot be bothered to update these tests everyday, versions have now be
adjusted to be slightly older to always go to the archive download.

use more general phpunit versions

Appveyor seems to have problems with redirects by php sometimes

Fix for Issue#1250 Footnotes break metadata abstract saving

New event for trimming recent changes and refactor lib/exe/indexer.php

Translation update (cs)

Translation update (it)

Translation update (ro)

The matches our scheme of where_data_what better

Translation update (ja)

authmysql and authpgsql were replaced by authpdo two releases ago.

fixed typos