WIP: Introduce Browser Permissions

[thiagowfx]

Bug: #587
Spec: https://www.w3.org/TR/permissions/

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Preview | Diff

[thiagowfx]

Removed, maybe to re-add later, maybe not:

CDDL:
? origin: text,

Algorithm:
1. Let |origin| be the value of the <code>origin</code> field of |command
   parameters| if present, or null otherwise, representing an [=/origin=].

Meant to refer to https://chromedevtools.github.io/devtools-protocol/tot/Browser/#method-setPermission

[thiagowfx]

cc @OrKoN

[OrKoN]

Let's draft it as an extension in https://www.w3.org/TR/permissions/

[thiagowfx]

Sounds good. Closing this PR, will rewrite it in the permissions spec repo: https://github.com/w3c/permissions/

For future updates refer to the Issue instead: #587.