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
13db1bd0a6