Arcyd: rename abdt_repoconfig -> abdt_repooptions

In anticipation of creating a new 'abdt_repoconfig', which will be used
for on-disk configuration of a repository, move the existing one out of
the way.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/acceptance_tests.sh
abdi_processargs: rename 'config' -> 'options'

Rename 'config' variables to 'options' so we can re-use config to mean
the on-disk 'hard' config.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/acceptance_tests.sh
abdi_processargs: use intermediate 'args' class

Pave the way towards using json data files instead of argparse, create
something that looks like the argparse 'args' that we can produce
independently.

Test Plan:
$ ./precommit.sh
$ ./testbed/arcyd/acceptance_tests.sh
Revert "abdi_processargs: use intermediate 'args' class"

This reverts commit d5d80829dd64b1827351280a08062692e172f326.
Arcyd: refactor, move repo args to new module

Test Plan:
$ ./precommit.sh
Arcyd: refactor, inline setup_parser

The split of which args are in abdi_processargs vs. abdcmd_processrepos
seems arbitrary, consoliate them in abdcmd_processrepos.

Test Plan:
$ ./precommit.sh
$ git grep abdi_processargs.setup_parser
Arcyd: refactor, extract phlsys_signal.set_exit_...

Extract the code to handle SIGTERM and do exit() to it's own module so
it's easier to re-use.

Test Plan:
$ ./precommit.sh
Arcyd: refactor, inline 'configure_sendmail'

Test Plan:
$ ./precommit.sh
Arcyd: refactor, move get_retry_delays()

Simplify abdi_processargs by moving get_retry_delays() to
abdcmd_processrepos - will simplify abdcmd_processrepos later.

Test Plan:
$ ./precommit.sh
Arcyd: refactor, extract new 'abdt_exhandlers'

Simplify abdi_processargs by extracting the exception handler factory
functions into their own module.

Test Plan:
$ ./precommit.sh
Arcyd: refactor, rename abdi_process(repo)args

Make the relationship of abdi_repoargs and abdi_processargs more obvious
by renaming abdi_processargs accordingly.

Rename 'run_once' to 'do' - there's no 'run_twice' or 'run_many' so it's
a bit redundant.

Test Plan:
$ ./precommit.sh