SigV4: Add support EC2 IAM role auth and possibility to toggle auth providers (#32444)

* wip: consume aws-sdk config in auth http settings

* fix typings

* use sdk regions

* use latest version of grafana/aws-sdk

* use newest sdk

* add comment

* bump sdk

* fix yarn lock file

* fix storybook issue

* upgrade aws-sdk. also use it in grafana ui

* remove not used config

* add aws-sdk as an external dep for grafana in the grafana ui rollup

Co-authored-by: Will Browne <will.browne@grafana.com>

package.json

@@ -201,7 +201,7 @@
   },
   "dependencies": {
     "@emotion/core": "10.0.27",
-    "@grafana/aws-sdk": "0.0.24",
+    "@grafana/aws-sdk": "0.0.3",
     "@grafana/slate-react": "0.22.9-grafana",
     "@popperjs/core": "2.5.4",
     "@reduxjs/toolkit": "1.5.0",