Enable paste on Hikvision cameras

Restores Cmd/Ctrl+V in password fields on Hikvision camera admin pages that block pasting.

Hikvision camera admin pages block pasting into the login password field. If you use a password manager with long, randomly generated passwords, you're forced to type them by hand every time you sign in. This extension fixes that. Press Cmd+V (Mac) or Ctrl+V (Windows/Linux) in the password field and your clipboard contents are written directly into the field — bypassing the page's paste blocker and pushing the value into the page's form model so the login actually works. Note, this works on my Hikvision cameras but I obviously haven't been able to test it on the enormous number of models they have. Sorry if it doesn't work on yours -- I'm unlikely to be able to add support without the camera to test with.