runtime(netrw): change netrw maintainer

runtime(netrw): change netrw maintainer

Dr. Chip retired some time ago and is no longer maintaining the netrw
plugin. However as a runtime plugin distributed by Vim, it important to
maintain the netrw plugin in the future and fix bugs as they are
reported.

So, split out the netrw plugin as an additional package, however include
some stubs to make sure the plugin is still loaded by default and the
documentation is accessible as well.

closes: #16368

Signed-off-by: Luca Saccarola <github.e41mv@aleeas.com>
Signed-off-by: Christian Brabandt <cb@256bit.org>