feat: Enable generation of compositions from subfolders

[akesser]

Signed-off-by: André Kesser andre.kesser@dkb.de

Description of your changes

We updated the algorithm to also find generate.yaml files in subfolders

I have:

• [x] Read and followed Crossplane's contribution process.
• [x] Run make reviewable test to ensure this PR is ready for review.

How has this code been tested

tested manually