Update the install-dynamic-plugins.py script to copy the extracted catalog-entities files to a configurable directory (via env var). The install methods will later configure this to point to /marketplace.

We should already have the necessary files extracted from the catalog index image when CATALOG_INDEX_IMAGE is set. We just need to additionally copy the catalog entities files to some configurable path.

Expected output is something like this (from the filesystem root):

├── marketplace
│   ├── catalog-entities
│   │   └── plugins/*.yaml
│   │   └── packages/*yaml
├── opt
│   ├── app-root
|    │   └──  src/<contains-rhdh-code>