Investigate SCSS comments parser for class reference

[bartaz]

During hackaton we discovered scss-comment-parser and CDocParser

scss-comment-parser: https://github.com/SassDoc/scss-comment-parser CDocParser: https://github.com/FWeinb/CDocParser

We could look into using one of them to parse custom annotations from the SCSS code to build class reference.

[bartaz]

Branch with POC after hackaton: https://github.com/canonical-web-and-design/vanilla-framework/tree/classreference-scss-docs-parsing

[bartaz]

Some notes from the code for reference:

https://github.com/canonical-web-and-design/vanilla-framework/blob/def0c74b0fb22779531d09a8b1286ff03cfdd762/scripts/create-class-references.js#L4-L23