* logging:
added JavaScript based filter mechanism
added logging configuration
replaced out calls to dbglog with new Logger calls
added convenience methods to log to our default facilities
added logviwer admin plugin
added log dir to git
central logging mechanism
This introduces a logger mechanism and a new data/log directory. This is
a first proof of concept. It's built on top of the new global error
handling mechanism
Things to discuss:
* should we adopt PSR-3 somehow? if yes, how and should plugins be able
to drop-in other psr3 loggers?
* how to configure which facilities shall be logged?
* should we implement a log deletion feature?
* is the log format sensible?
* should we implement a log viewer admin plugin?
* should logging trigger events (it should maybe replace the
deprecation event)
Some plugins, for example the move plugin, use their own handler class.
We need to give these plugins time to adjust their code.
This should restore the functionality of the move plugin. We still need
to extract the handler class itself.
It also adds another debug method for triggering the deprecation event,
since none of the two existing methods are suitable here. This
dbgCustomDeprecationEvent method should be used sparingly and only where
the other two don't work.
Co-authored-by: Phy <git@phy25.com>
Andreas Gohr