Migrate config to KV data format (#8392)

- adding oauth support to MinIO browser (#8400) by @kanagaraj
- supports multi-line get/set/del for all config fields
- add support for comments, allow toggle
- add extensive validation of config before saving
- support MinIO browser to support proper claims, using STS tokens
- env support for all config parameters, legacy envs are also
  supported with all documentation now pointing to latest ENVs
- preserve accessKey/secretKey from FS mode setups
- add history support implements three APIs
  - ClearHistory
  - RestoreHistory
  - ListHistory
- add help command support for each config parameters
- all the bug fixes after migration to KV, and other bug
  fixes encountered during testing.

cmd/handler-utils_test.go

@@ -26,6 +26,8 @@ import (
 	"reflect"
 	"strings"
 	"testing"
+
+	"github.com/minio/minio/cmd/config"
 )
 
 // Tests validate bucket LocationConstraint.
@@ -81,7 +83,7 @@ func TestIsValidLocationContraint(t *testing.T) {
 	}
 
 	for i, testCase := range testCases {
-		globalServerConfig.SetRegion(testCase.serverConfigRegion)
+		config.SetRegion(globalServerConfig, testCase.serverConfigRegion)
 		_, actualCode := parseLocationConstraint(testCase.request)
 		if testCase.expectedCode != actualCode {
 			t.Errorf("Test %d: Expected the APIErrCode to be %d, but instead found %d", i+1, testCase.expectedCode, actualCode)