Parsing comma separated CSPs + cleanup

[MaxNad]

This PR implements parsing of comma separated CSPs. It is meant to be a conversation starter and I do not mind reworking the code or the PR itself to make it simpler to merge.

Users can provide an array of CSPs (To interact with HTTP libraries that do not concatenate headers) or a comma separated string (as provided by the http lib in nodejs). This should fix #10 and #25.

While working on the implementation, I had to change some of the rules to take into account the "AND" behaviour of multi-CSPs. I took the opportunity to add check (Ex. #54 and other checks commonly found during review of CSPs)

Since the library now has to handle a list of directive maps instead of a single map, the inner-working have changed and I took the liberty of moving the version number to 2.0.0 to indicate potential breaking changes. The upper-level interactions (Creating a parser, recovering the CSP object, passing the CSP object to the evaluator and obtaining the results, etc.) should remain the same.

To sum up, here is the list of changes:

• Comma separated CSP parsing (CSP with commas are parsed in a confusing way #10 and improve parsing of multi-value CSP headers #25)
• Implemetation of 3 new checks
  • Presence of wasm-unsafe-inline (Hosted CSP Evaluator doesn't recognize 'wasm-unsafe-eval' #54)
  • Missing form-action directive (form-action doesn't fall back on default-src and could be used for phishing)
  • Rules related to 'style-src' that could be used for phishing
• Cleanup of bypass endpoints that no longer resolve (Newrelic endpoint no longer exists #62)
• Refactor and linting based on gts
• Bump to version 2.0.0

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