[cleanup] Remove deprecated/not implemented rcstream methods
[cleanup] Remove deprecated/not implemented rcstream methods

rcstream support was removed with 3.0.20171212 in favour of eventstreams.
The old path methods are obsolete.
- remove rcstream* methods from Family
- remove rcstream_host from WikimediaFamily

Change-Id: I5b5c93cc6b1fe5a6b3554d160ac50522ab8e550d

PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core,wikimedia/pywikibot-core