Tool for quick page imports

[kedrzu]

Changes

It's a tool, that I created to test prerendering performance. It allows to relatively quickly create many pages in webiny for testing purposes.

Because it uses several third-party libraries, I added it as a package in /tools instead of /scripts and added /tools/* to yarn workspaces config. I made the package private so it won't be published.

How Has This Been Tested?

Manually. Check README.md for details.