chg: dev: Unify handling of the program name in all the utilities

There were several methods how we used 'argv[0]'.  Some programs had a
static value, some programs did use isc_file_progname(), some programs
stripped 'lt-' from the beginning of the name.  And some used argv[0]
directly.

Unify the handling and all the variables into isc_commandline_progname
that gets populated by the new isc_commandline_init(argc, argv) call.

Merge branch 'ondrej/unify-handling-of-the-program-name' into 'main'

See merge request isc-projects/bind9!10502