Be able to add extra (short) options from the 'applet' to
the main application. Use this to print the help mentioning
app specific options, pass the getopt string and handle the
command line parsing for it.
Change cell_log to keep the logname in the app_cell_log.c
and then access it from the cell_log.c implementation.
Make it possible that each l23 app can inject the copyright string,
also prepare to have callbacks for the config handling and other
places. This will be useful to add app specific config options.
This split the headers and adapt the source.
We use osmocom/bb as a prefix because libosomore also
uses osmocom and generic names such as misc & common could
conflict in the future.
Signed-off-by: Sylvain Munaut <tnt@246tNt.com>