Draft: Add keyword arguments to get_particles Issue #412

Add some keywords, for example get_particles( Source =HLT2, line = 'line_name') to try and reduce instances of people getting paths wrong, upper/lower case mismatch etc.

https://mattermost.web.cern.ch/lhcb/pl/dj3sq6kdtjdamcybiiq1znch6r

You can call get_particles with line name and HltsourceID (HLT2, Spruce, Turbo...), also checking for case sensitivity in the source... get_particles(source = 'HltsourceID', line = 'line_name')