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/web-handler-context.go

@@ -179,6 +179,12 @@ func (args *LoginArgs) ToKeyValue() KeyValueMap {
 	return km
 }
 
+// ToKeyValue implementation for LoginSTSArgs
+func (args *LoginSTSArgs) ToKeyValue() KeyValueMap {
+	km := KeyValueMap{}
+	return km
+}
+
 // ToKeyValue implementation for GetBucketPolicyArgs
 func (args *GetBucketPolicyArgs) ToKeyValue() KeyValueMap {
 	km := KeyValueMap{}