feat: update docker and pipeline

- Add workflow to publish to GHCR
- Add workflow to build Docker image
- Add zap2xmlrc config example
- Update Dockerfile to run continuously

.zap2xmlrc-example

@@ -0,0 +1,20 @@
+start=0
+days=7
+ncdays=0
+ncsdays=0
+ncmday=-1
+retries=3
+user=user
+pass=password
+cache=/config/cache
+icon=/config/icons
+trailer=/config/trailers
+lang=en
+proxy=http://localhost:8080
+outfile=/xmltv/xmltv.xml
+outformat=xmltv (or 'xtvd')
+lineuptype=type (xtvd only - Cable/CableDigital/Satellite/LocalBroadcast)
+lineupname=name (xtvd only)
+lineuplocation=location (xtvd only)
+lineupid=X:80000
+postalcode=01010