Add optional master password to protect the "proceed anyway" bypass on blocked pages

[corpus96]

Add an optional "master password" feature that adds a layer of protection to the src/js/document-blocked.js bypass flow.

Benefits: This could be useful is you share devices, parenting or simply want to add another layer of privacy/security to your domain filter list.

User could enable a passkey from the dashboard's Settings pane, where a password is derived and stored securely.

The feature could be disabled at any time from Settings by re-entering the current password.

Bypassing the document.js screen should only be possible if the user types the correct passkey and the Proceed or "Don´t show me again" button is grayed out until then.

Note: I am using the word "password" or "passkey" to make the idea more clear, but the intent is not to threat it as a secret that needs complex security checks and the base "secure password requirements". Intention is to add another layer of privacy, storing the passkey locally should be enough and optionally salt the string.

[gothic-bum]

From the uBO wiki, see: Does uBO have a parental control or password protection?

And regarding:

Bypassing the document.js screen should only be possible if the user types the correct passkey and the Proceed or "Don´t show me again" button is grayed out until then.

A user could simply disable uBO and then access the site.

[krystian3w]

Only if the user knows that add-ons can be disabled and the browser does not use policies prohibiting the deactivation or removal of the add-on.

[krystian3w]

Rather, the root/superadmin password should be used for deactivation in Dashboard.