Pre-release update

i) "active" grabbers that are failing

Userland testing has revealed some persistent failures in a couple of
"active" grabbers:

- tv_grab_se_swedb - empty upstream data files
- tv_grab_pt_vodafone - upstream site changes

I have disabled these in the Makefile and raised issues on Github.
se_swedb may not be needed with the new eu_xmltvse grabber.
pt_vodafone may be salvageable after updating the grabber for the
relevant site changes.


ii) deprecated and disabled grabbers

I have also removed the following deprecated and disabled grabbers:

tv_grab_eu_dotmedia
tv_grab_se_tvzon
tv_grab_es_laguiatv
tv_grab_fr_kazer
tv_grab_in_toi
tv_grab_nl
tv_grab_dtv_la


iii) build testing

I have updated several Dockefiles to support build testing of our code
on the most recent releases of Debian, Ubuntu and Fedora. XMLTV is not
yet packaged for CentOS 8, and a few Perl modules need to be packaged
too before I will switch to the CentOS 8 dockerfile.

Thanks,
Nick