Make late runtime processor configurable for CLI commands

Problem/Motivation

#3163002: Make late runtime processor compatible with drush made the late runtime processor compatible with Drush. This means that the purge queue will be checked when running arbitrary Drush commands. This lead to some arguments that this was not expected behavior when using CLI commands, the Purge module already has CLI commands for processing and the Late Runtime Processor should only handle web requests.

It was argued that enabling processing for CLI commands should have been a configuration option.

Steps to reproduce

None.

Proposed resolution

Now processing the purge on CLI commands is the default so instead it should be a configuration option to disable processing for CLI commands.

Remaining tasks

User interface changes

- Add a configuration form for the Late Runtime Processor with a checkbox for disabling it on CLI commands.

API changes

None.

Data model changes

None.