Clear registry cache using fpm clean --registry-cache

[minhqdao]

• Clear registry cache using the --registry-cache command option for fpm clean.
• Add tests for --registry-cache, --skip and --all.
• Throw error if --skip and --all are used simultaneously.
• Fix typo clean_call --> clean_all.
• Add to fpm help.

Things to discuss

• The rm -rf <registry-cache> command is executed no matter if the folder exists or not. This isn't problematic. But we could warn the user if the folder doesn't exist, consistent to what happens when the user tries to remove the build folder if it doesn't exist.
• One could additionally ask the user to confirm the deletion of the registry cache because it potentially affects all projects on the system.

How to test

• Run fpm run -- clean --registry-cache.
• Use in conjunction with --skip and --all options.

[henilp105]

Thanks @minhqdao, Looks good to me.

[henilp105]

Thanks @perazz @minhqdao , Looks good to me , Will merge in a few hours for the new fpm release.

[henilp105]

Merging!