Create internet access service and shim internet access out

[tjcouch-sil]

Create an internet access service on the papi, and shim out internet access so extension developers can't access the internet outside our avenues. Probably pretty much just perfectly mirror the fetch api (maybe even just pass the args straight to it).

Depends on #30

Closely related to #75, but not quite dependent on it.

[tjcouch-sil]

Some light reading on the subject:
https://cheatsheetseries.owasp.org/cheatsheets/Cross_Site_Scripting_Prevention_Cheat_Sheet.html - one to keep around
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy
https://github.com/cure53/DOMPurify
https://developer.mozilla.org/en-US/docs/Web/API/Document/createElement
https://developer.mozilla.org/en-US/docs/Web/API/HTMLImageElement/Image
https://developer.mozilla.org/en-US/docs/Web/API/HTMLFormElement
https://developer.mozilla.org/en-US/docs/Web/API/HTMLAnchorElement
https://developer.mozilla.org/en-US/docs/Web/API/XMLHttpRequest/Using_XMLHttpRequest
https://developer.mozilla.org/en-US/docs/Web/API/Fetch_API
https://www.google.com/search?q=prevent+requests+outside+of+your+website&rlz=1C1GCEA_enUS1002US1002&oq=prevent+requests+outside+of+your+website&aqs=chrome..69i57j33i160l3.10095j0j7&sourceid=chrome&ie=UTF-8
https://stackoverflow.com/questions/61803412/prevent-a-web-application-from-making-http-requests-outside-a-domain-whitelist
https://stackoverflow.com/questions/60406933/prevent-request-to-another-domain
https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Content-Security-Policy/connect-src
https://security.stackexchange.com/questions/64055/how-to-ensure-that-only-my-single-page-app-can-make-requests-to-an-api
https://medium.com/snips-ai/how-to-block-third-party-scripts-with-a-few-lines-of-javascript-f0b08b9c4c0

[tjcouch-sil]

Created some issues as follow-ups from this one:
#85
#86
#87
#88
#89
#90
#91