A new endpoint to retrieve experiment configuration data (maybe duplicate of metadata?)

From a meeting today;

We will need an endpoint in the API to retrieve experiment data. The current case where we will need it, requires the API to retrieve FDB data from experiments executed with Autosubmit.

At some point users will run autosubmit create and have a YAML configuration with some keys that we would like to expose via API calls.

e.g.:

• User contains several YAML files
• Some of these YAML files contain keys that correspond to values used for FDB (read/write)
• Users would run their workflows, as they normally do
• At some point users would then want to query the API, e.g. (I'm making up the call without looking at swagger) /api/v4/experiment/a000/$new-end-point? and retrieve the configuration

This configuration retrieved would be useful if it was retrieved in a custom format. Maybe if users provided a list of keys that correspond to the FDB settings.

cc @agayayav