Add more LA County bus and regional rail operators

[DefenestratingWizard]

Added entries for:

• Burbank Bus
• Glendale Beeline
• Santa Clarita Transit
• AVTA
• Metrolink

this is my first PR so I may have made a mistake

[mlundblad]

Thanks! Looks good! (there's a couple of other feeds failing now, but those are unrelated to these)