fix: make demo #49

[yunlzheng]

Signed-off-by: yunl.zheng yunl.zheng@gmail.com

Description of your changes

• The folder of crds is change to package/crds/
• The cluster/examples/database/resource_class.yaml is already rename to cluster/examples/database/rds.yaml
• cluster/examples/database/rds.yaml providerConfigRef name match to cluster/examples/provider.yaml

Fixes #

make demo fail

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

Run

make demo

should provision a demo environment successful.