Docker Build blog post (#4211)

* Docker-Build blog post

* Remove other examples

* updates to blog

* updates to blog

* changes to blog

* update to table in blog

* update to table

* Add comments to code, fold "Why a new provider?" into intro

* adding few of Isaac's suggestion

* docker-build to Docker Build in Txt and date change

* updates to small changes suggested by Luke

* changing Pulumi Docker to Docker provider

* updates to conclusion

* Feedback

* hange Pulumi Docker to Docker

* adding links

* updates to links

* Add a dbc video

* fix lines + small edits

* fix link

* fix markdown

* fix more markdown

* image: s/Docker-Build/Docker Build

* added notes for the migration code

* Update themes/default/content/blog/docker-build/index.md

fixed awkward phrasing

* last change - Luke's suggestion

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Co-authored-by: tejavar <[email protected]>
Co-authored-by: diana esteves <[email protected]>
Co-authored-by: isaac-pulumi <[email protected]>