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/generic-handlers.go

@@ -196,7 +196,7 @@ func guessIsBrowserReq(req *http.Request) bool {
 		return false
 	}
 	aType := getRequestAuthType(req)
-	return strings.Contains(req.Header.Get("User-Agent"), "Mozilla") && globalIsBrowserEnabled &&
+	return strings.Contains(req.Header.Get("User-Agent"), "Mozilla") && globalBrowserEnabled &&
 		(aType == authTypeJWT || aType == authTypeAnonymous)
 }