Add microsoft oauth2 providers (#16544)

* Clean up oauth2 providers

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Add AzureAD, AzureADv2, MicrosoftOnline OAuth2 providers

Signed-off-by: Andrew Thornton <art27@cantab.net>

* Apply suggestions from code review

* remove unused Scopes

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: techknowlogick <techknowlogick@gitea.io>

vendor/github.com/markbates/going/LICENSE.txt

@@ -0,0 +1,22 @@
+Copyright (c) 2014 Mark Bates
+
+MIT License
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

vendor/github.com/markbates/going/defaults/defaults.go

@@ -0,0 +1,36 @@
+package defaults
+
+func String(s1, s2 string) string {
+	if s1 == "" {
+		return s2
+	}
+	return s1
+}
+
+func Int(i1, i2 int) int {
+	if i1 == 0 {
+		return i2
+	}
+	return i1
+}
+
+func Int64(i1, i2 int64) int64 {
+	if i1 == 0 {
+		return i2
+	}
+	return i1
+}
+
+func Float32(i1, i2 float32) float32 {
+	if i1 == 0.0 {
+		return i2
+	}
+	return i1
+}
+
+func Float64(i1, i2 float64) float64 {
+	if i1 == 0.0 {
+		return i2
+	}
+	return i1
+}