Chrome extension code cleanup

[max-ostapenko]

While I was trying to fix #66, I expected stripping the code to only the functional features of the extension would help to understand and resolve the issues. This indeed should make supporting the extension easier in future for testing purposes and getting contributions that are reliably tested.

Adjustments:

• removed internationalization, paid features, server requests (for simpler code)
• turned caching to FALSE by default (since this extension should be helpful testing the new rules)
• dynamic icon to TRUE (so that it's easy to distinguish from the official extension)
• direct link to report an issue in the HTTPArchive's fork