Embed code analysis rules

[rimutaka]

Code analysis rules live in stm_rules folder. It is the only external resource distributed with the executable, apart from Git itself. The distribution will be limited to just a single executable if the rules are embedded.

• [x] remove all mention of --rules from help.rs
• [x] update ReadMe
• [x] check if CodeRules::file_ext_regex and CodeRules::file_name_as_ext_regex are still used anywhere
• [x] add public profile to welcome msg in YOUR DIRECTORY PROFILE: https://stackmuncher.com/?dev={pub_key}

[rimutaka]

There should be a way to provide an alternative location of the rules folder that is not embedded, but it's quite a bit of work.

It would be useful for someone to adjust the rules without recompiling the executable.