Proposal to standardize the code structure of Dapr repositories

@marcduiker and I discussed the experience for new users and contributors of Dapr. One of the observations is that currently the contents of repositories is not uniform, which means their experience can vary depending on where they land first. The image shows a table with Dapr repos in columns and their contents in rows below.

The proposal part of this issue is open for discussion :-)

For instance, dapr/dapr contains 6 default repo files and the other repos have less. Do we want all repos to have codeowners, governance, and security files?

Another example: should all repos have a folder for documentation? And should it be called docs, daprdocs, sdkdocs, etc?