The Composer samples all need READMEs

[JonathanFingold]

Sample information

1. Sample type: [\samples]
2. Sample language: [dotnetcore] and [nodejs]
3. Sample name: all projects under composer-samples

Describe the bug

Nearly every folder from BotBuilder-Samples/composer-samples/ down to the solution folders is missing a README file.

To Reproduce

Steps to reproduce the behavior:

1. Go to https://github.com/microsoft/BotBuilder-Samples/tree/main/composer-samples
2. See error: there are no README files here or in any of the subfolders.

Expected behavior

1. At logical points in the folder structure, a directory will have a README providing information on what's in the directory structure and links to relevant topics and more information.
2. Some of the C# package/component sample have a minimal README, but most project folders do not.

Additional context

It would help to have README files to link to from the docs.