feat: Settings - Decouple from shield

[najdanovicivan]

Description Decouple settings library so it is not required. Related to #1215

Checklist:

• [x] Securely signed commits
• [x] Component(s) with PHPDoc blocks, only if necessary or adds value
• [ ] Unit testing, with >80% coverage
• [ ] User guide updated
• [x] Conforms to style guide

[TwistedAndy]

Yes, it would be great to decouple Shield and Settings packages. Personally, I don't see a lot of sense of having the Settings dependency here, because CodeIgniter already has BaseConfig to handle settings.

[najdanovicivan]

@datamweb What else is needed for this one to be merged ?

[datamweb]

@najdanovicivan I'm currently on mobile and need to review this PR on my PC. I'll get back to it soon.