update msg command with ability to accept input file

[scgbckbone]

• msg-file cmd removed and instead it's functionality partially implemented in normal msg cmd (lot dupe lines, & generally does not deserve its own cmd)
• I would gladly remove -o/--output option as it can be simulated with redirections (but keep for now)
• compared to msg-file this does not creates output file by default, but user has to provide it as a -o/--output parameter

[scgbckbone]

@portlandhodl we can adjust according to your needs

[portlandhodl]

I like it!

I created the new command to avoid this, regardless if you are okay with it I am too! The main thing is that the functionality is present.

@click.option('--in-file', is_flag=True,
              help='If present, argument MESSAGE is treated as path to input file containing message'