Update README.md (#363)

* Update README.md

* update README.md

* add empty lines

* update links

* update words

* update README.md

* update README.md

* update README.md

* update README.md

* update README.md

* update README.md according to comments

* update README.md according to comments

* remove AZURE_CORE_OUTPUT from workflow examples

* add warning for MI and add links for Azure CLI and Azure PowerShell

* workaround markdownlint issue

* fix typo

* update for Azure CLI notification

* update words