Two factor authentication support (#630)

* Initial commit for 2FA support

Signed-off-by: Andrew <write@imaginarycode.com>

* Add vendored files

* Add missing depends

* A few clean ups

* Added improvements, proper encryption

* Better encryption key

* Simplify "key" generation

* Make 2FA enrollment page more robust

* Fix typo

* Rename twofa/2FA to TwoFactor

* UNIQUE INDEX -> UNIQUE

models/models.go

@@ -105,6 +105,7 @@ func init() {
 		new(Notification),
 		new(IssueUser),
 		new(LFSMetaObject),
+		new(TwoFactor),
 	)
 
 	gonicNames := []string{"SSL", "UID"}