Change READMEs for MAP and MAP-init

[dbericat]

Having the same README for the init initial container and MAP to add the 3rd party/non-Python software was a little confusing to me.

I would change the description to clarify the process and call out the limitation. :)

[tomaroberts]

For ref: https://stackoverflow.com/questions/73280419/specifying-which-readme-is-displayed-under-a-github-package-connected-to-a-repos

Need a workaround / some form of versioning so that map and map-init packages have different README files