Use tabCapture API

[vantezzen]

Currently, the extension uses direct media element access to analyze the volume. To improve issues with CORS, this can instead be changed to work on a per-page basis using the Chrome "tabCapture" API.

Pros

• Makes the extension work on far more pages (especially CORS-related issues)
• May even work on pages that don't use the standard HTML5 audio elements when adding custom page drivers

Cons

• This change is NOT compatible with Firefox
  • The feature uses the "tabCapture" API which is not implemented in Firefox and won't get in the near future (https://bugzilla.mozilla.org/show_bug.cgi?id=1391223)
  • I plan on keeping support for the current Skip Silence 4, keeping compatibility with Firefox but not having background-level capturing or making the extension compatible with both APIs based on availability
• This change is (currently) NOT compatible with Manifest v3
  • Neither tabCapture nor AudioContext is available there (https://bugs.chromium.org/p/chromium/issues/detail?id=1214847)
  • Manifest v2 is available until 01/2023 so we can hope Chrome fixes this until then
• multiple media elements on a SINGLE page cannot be analyzed independently, though I doubt anyone uses Skip silence like that

TODO

• Change Silence Skipper to work on a per-page instead of per-element level
• Switch Silence Skipper to using tabCapture API
• Make it work for iFrames (e.g. Google Drive Incompatible service - vidoes on Google Drive #118)
• Public beta testing