This commit prepares the documentation directories for future tutorials organized by directory.
Also, it moves the Angular Libraries topic from the Tutorials section to Developer Guides in TOC
PR Close#48162
In #37182 the in-memory-web-api module was moved into this repo.
Copy the reamde into this repo with the following changes:
* Removed Travis badges
* Updated github links to point to Angular repo
* Removed 'running tests' as it is no longer relevant
Fixes#40190
PR Close#40203
