Improvements to the doc (#1989)

* 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

* updated contributing.md

* fixed broken links & added missing links in doc, improved structure

* fixed link in wsl setup

* fixed server link, added https cloning in yarn-setup

* removed package-lock.json

* added doc card, admonitions

* removed underline from nav buttons

docs/src/theme/icons.js

@@ -2,6 +2,7 @@ export {
   TbApps,
   TbArrowBackUp,
   TbArrowBigRight,
+  TbArticle,
   TbBolt,
   TbBrandFigma,
   TbBrandVscode,