Add --fuzzing-ratio to CLI

[Markoutte]

Description

1. Now, CLI can be set with specific fuzzing ration instead of default 0.1. If no option is specified, then the default one is used.
2. Source option is not required anymore. When --source option is absent then no javadocs is generated

Self-check list

• [x] I've set the proper labels for my PR (at least, for category and component).
• [x] PR title and description are clear and intelligible.
• [x] I've added enough comments to my code, particularly in hard-to-understand areas.
• [ ] The functionality I've repaired, changed or added is covered with automated tests.
• [ ] Manual tests have been provided optionally.
• [ ] The documentation for the functionality I've been working on is up-to-date.