feat(Browser extension): Firefox support

Iteration of the 'View with Threat Composer' browser extension, with compatibility focused on Mozilla Firefox

This aims to enable one to “view web accessible Threat Composer exports (.tc.json) with one click”. Note that this has a bake-in version of the Threat Composer react app, it is not dependant on (nor can it use) a remote hosted version.

The extension supports the following integrations where a ‘View in Threat Composer’ button is added to the page:

GitHub Code Browser
Amazon Code Catalyst
‘View Raw’ anywhere online so long as the URL includes reference to .tc.json (Note: on Firefox it does not work on githubusercontent.com due to the sandbox CSP directive)

awslabs / threat-composer

feat(Browser extension): Firefox support #74