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

vendor/github.com/boombuler/barcode/utils/base1dcode.go

@@ -0,0 +1,48 @@
+// Package utils contain some utilities which are needed to create barcodes
+package utils
+
+import (
+	"image"
+	"image/color"
+
+	"github.com/boombuler/barcode"
+)
+
+type base1DCode struct {
+	*BitList
+	kind     string
+	content  string
+	checksum int
+}
+
+func (c *base1DCode) Content() string {
+	return c.content
+}
+
+func (c *base1DCode) Metadata() barcode.Metadata {
+	return barcode.Metadata{c.kind, 1}
+}
+
+func (c *base1DCode) ColorModel() color.Model {
+	return color.Gray16Model
+}
+
+func (c *base1DCode) Bounds() image.Rectangle {
+	return image.Rect(0, 0, c.Len(), 1)
+}
+
+func (c *base1DCode) At(x, y int) color.Color {
+	if c.GetBit(x) {
+		return color.Black
+	}
+	return color.White
+}
+
+func (c *base1DCode) CheckSum() int {
+	return c.checksum
+}
+
+// New1DCode creates a new 1D barcode where the bars are represented by the bits in the bars BitList
+func New1DCode(codeKind, content string, bars *BitList, checksum int) barcode.Barcode {
+	return &base1DCode{bars, codeKind, content, checksum}
+}