Update README and Documentation (#1875)

* Added Overview page

* Revised Getting Started page

* Minor revision

* Edited readme, minor modifications to docs

* Removed sweep.yaml, .devcontainer, .ergomake

* Moved security.md to .github, added contributing.md

* changes as per code review

docs/src/theme/icons.js

@@ -25,4 +25,6 @@ export {
   TbTopologyStar,
   TbVocabulary,
   TbZoomQuestion,
-} from "react-icons/tb";
+  TbRocket
+} from "react-icons/tb";
+