feat: support required extensions

[mbiagetti]

initial support for extensions dependencies

introduce a new field in the metadata spec to define a list of required extensions

supposing a metadata file like

metadata = {
  name                     = "pgrouting"
  sql_name                 = "pgrouting"
  image_name               = "pgrouting"
  shared_preload_libraries = []
  extension_control_path   = []
  dynamic_library_path     = []
  ld_library_path          = []
  auto_update_os_libs      = false
  required_extensions      = [
      "postgis",
  ]

  versions = {
    bookworm = {
      "18" = ":4.0.0+dfsg-1.pgdg12+1"
    }
    trixie = {
      "18" = "4.0.0+dfsg-1.pgdg13+1"
    }
  }
}

the command generate-testing-values command will generate the proper extensions like

dagger \
call \
-m ./dagger/maintenance/ \
generate-testing-values --target pgrouting --extension-image ghcr.io/cloudnative-pg/pgrouting:4.0.0-18-bookworm export --path=pgrouting/values.yaml

extensions:
    - dynamic_library_path: []
      extension_control_path: []
      image:
        reference: ghcr.io/cloudnative-pg/pgrouting:4.0.0-18-bookworm
      ld_library_path: []
      name: pgrouting
    - dynamic_library_path: []
      extension_control_path: []
      image:
        reference: ghcr.io/cloudnative-pg/postgis-extension:3.6.1-18-bookworm
      ld_library_path:
        - /system
      name: postgis
name: pgrouting
pg_image: ghcr.io/cloudnative-pg/postgresql:18-minimal-bookworm
sql_name: pgrouting
version: 4.0.0

closes #18

[GabriFedi97]

I see we are not adding all the extensions defined as dependencies when we create the Database CR in the automated tests. CNPG doesn't create the extensions with the CASCADE option so all the required extensions need to be explicitly created beforehand.

[NiccoloFei]

I see we are not adding all the extensions defined as dependencies when we create the Database CR in the automated tests. CNPG doesn't create the extensions with the CASCADE option so all the required extensions need to be explicitly created beforehand.

This will be added as part of #92, given that in #92 we are adding an adhoc field in the values.yaml to customize the spec.extensions section of a Database.