Various new optional permissions (#6112)
Various new optional permissions (#6112)

Adding the following as optional permissions:
* browsingData as per [1630417](https://bugzilla.mozilla.org/show_bug.cgi?id=1630417)
* pkcs11 as per [1630418](https://bugzilla.mozilla.org/show_bug.cgi?id=1630418)
* proxy as per [1548011](https://bugzilla.mozilla.org/show_bug.cgi?id=1548011)
* sessions as per [1630414](https://bugzilla.mozilla.org/show_bug.cgi?id=1630414)

Co-authored-by: Richard Bloor <b757ed502e9cd53032b93a1a07cebbdf1c211aaa@atlassian.com>
mdn/browser-compat-data,mdn/browser-compat-data,chrisdavidmills/browser-compat-data,chrisdavidmills/browser-compat-data