feat(clafrica): implement extension via scripting

[pythonbrad]

Issue

• Extension via scripting #67

TO-DO

• apply the DRY in the config.rs
• Real test on a windows platform.
• Implement scripting at the level of the processor.
• Implement scripting at the level of the translator.

Change

• The Rhai scripting language is supported as embedded scripting language.

[coveralls]

Pull Request Test Coverage Report for Build 6037932488

• 91 of 93 (97.85%) changed or added relevant lines in 3 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.2%) to 99.305%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
clafrica/src/config.rs	63	65	96.92%

Totals
Change from base Build 6024482461:	-0.2%
Covered Lines:	857
Relevant Lines:	863

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💛 - Coveralls

[pythonbrad]

I don't want to overload this pull request. I think that it's enough like that.