Updated test to be blocked on Bugzilla issue.

We had a CLI gpg test for Redmine #4480 which is now broken due to
Bugzilla #1108227, so I'm updating the existing test to reflect this new
blocker.
Merge pull request #878 from omaciel/update_gpg_cli_test

Updated test to be blocked on Bugzilla issue.
Update module-level documentation

Add high-level documentation explaining the layout of the codebase.
Increasing the timeout for CLI commands.

Increased the timeout for a CLI command from 60 to 120 seconds to see if
we can get rid of some false negative tests.
Merge pull request #880 from omaciel/longer-cli-timeout

Increasing the timeout for CLI commands.
Merge pull request #879 from Ichimonji10/docs

Update module-level documentation