docs: fix some typos in rtcomps.txt

These typos broke several of our block diagram images.
make all docs packages Provide linuxcnc-doc

linuxcnc-doc is now a virtual package provided by any of our translated
docs.

linuxcnc.deb has "Recommends: linuxcnc-doc-en | linuxcnc-doc", which
will make it prefer linuxcnc-doc-en but accept any of the translated docs.

Multiple translated doc packages can be installed simultaneously, just
like before.
docs: split out doc source files by language

This is only a reorg for visual clarity, none of the make variables
actually changed values.
docs: split out pdf targets by language

This is only for visual clarity in the makefile, none of the variables
change value.
deb: dont build german docs package
docs: remove german docs

These were added as copies from the english docs, with the intent
of getting translated into german, but no one ever translated them.
This makes them misleading and outdated, so remove them.

If someone wants to maintain a german translation of the docs we'll
create them again.
docs: remove some stray references to polish docs

I'm not sure how these non-polish docs came to reference polish docs,
but they shouldn't.
docs: remove an old comment

Not sure what this comment originally meant, but it's surely no longer
useful.
deb: dont build polish docs package
docs: remove polish docs

These were added as copies from the english docs, with the intent
of getting translated into polish, but no one ever translated them.
This makes them misleading and outdated, so remove them.

If someone wants to maintain a polish translation of the docs we'll
create them again.