[Cashtab] Remove google analytics call from extension

Summary:
Extension at manifest v3 is rejected from Chrome store due to lingering calls to google analytics. Code was refactored so the calls were not used in the extension, but that is insufficient -- the code must not exist in the repo.

meta tags and link info not associated with the extension is also moved to the "webapp-only" conditionally-rendered section in index.html

Test Plan:
npm run extension, navigate to extension/dist/static/js/main.*.js, ctrl+f 'analytics' and only 1 match, not in a link.
npm run build, navigate to cashtab/build/static/js/main.*.js, ctrl+f 'analytics', 8 matches including links

Reviewers: #bitcoin_abc, Fabien

Reviewed By: #bitcoin_abc, Fabien

Subscribers: Fabien

Differential Revision: https://reviews.bitcoinabc.org/D15054