allow running in web pages using a meta tag

[hatemhosny]

if a web page needs to run the extension without being in the allowlist, this meta tag would trigger activating the functionality of the extension:

<meta name="codeium:type" content="monaco">

This is a demo: https://codeium.livecodes.pages.dev/

see https://github.com/Exafunction/codeium-chrome/issues/28