Move BMC options and help text to bmc_util [depends: 3565]

[peterschrammel]

Based on #3565, review only last commit

• Each commit message has a non-empty body, explaining why the change was made.
• Methods or procedures I have added are documented, following the guidelines provided in CODING_STANDARD.md.
• The feature or user visible behaviour I have added or modified has been documented in the User Guide in doc/cprover-manual/
• Regression or unit tests are included, or existing tests cover the modified code (in this case I have detailed which ones those are in the commit message).
• My commit message includes data points confirming performance improvements (if claimed).
• My PR is restricted to a single feature or bugfix.
• White-space or formatting changes outside the feature-related changed lines are in commits of their own.

[allredj]

🚫
This PR failed Diffblue compatibility checks (cbmc commit: bb31b47).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/94899676
Status will be re-evaluated on next push.
Please contact @peterschrammel, @thk123, or @allredj for support.

Common spurious failures:

• the cbmc commit has disappeared in the mean time (e.g. in a force-push)
• the author is not in the list of contributors (e.g. first-time contributors).

The incompatibility may have been introduced by an earlier PR. In that case merging this
PR should be avoided unless it fixes the current incompatibility.

[tautschnig]

Would you mind adding an issue or are you tracking this in some way?

[peterschrammel]

That will be the result as soon as I reach the top of this DAG of PRs.

[tautschnig]

Marking do-not-merge until depended-on PR is merged.

[peterschrammel]

Marking do-not-merge until depended-on PR is merged.

Can we assume that "dependent" implies "do not merge" to reduce the number of labels?
Or rename "dependent" to "dependent - do not merge".

[tautschnig]

Or rename "dependent" to "dependent - do not merge".

+1 on this - I'd like to avoid implicit information.

[allredj]

✔️
Passed Diffblue compatibility checks (cbmc commit: 8d150f0).
Build URL: https://travis-ci.com/diffblue/test-gen/builds/96787768