Feature: PBKDF2-SHA512 support

[GWuk]

Add PBKDF2-SHA512 support

Linked papers at https://www.cl.cam.ac.uk/~dl551/pwdhash/ for motivation

• optionally use PBKDF2-SHA512
• add options page for PBKDF2-SHA512 support (salt + iterations + mode)
• mark active PwdHash with red border on password field for PwdHash "legacy" mode and green border for PBKDF2-SHA512 mode
• Shift-F2 for "legacy" mode when PBKDF2-SHA512 enabled in options

Implementation see pull request for legacy repo https://github.com/pnebert/pwdhash-firefox/pull/2

[T-X]

Just noticed that pwdhash seems to have gotten some extra care and was turned into a webextension. Awesome!

Since the linked pull-request is dead, here is what I had added some years ago to the legacy version:

https://github.com/T-X/pwdhash

Which added sha512 and key stretching. Not sure anymore whether the key stretching I added is actually PBKDF2 or not... long time ago.