Listing of PSR needs to allow finding the ID's for relevant resources

[Pierre-VF]

In the metadata description ( https://github.com/carbon-data-specification/Power-Systems-Data/blob/main/specifications/cdsc-wg2-03.md ) under 3.3.1 ( /power-system-resources ), filters need to be expands to be usable with adequate scopes.

Relevant scopes might include:

• Country
• Region

Where the values for these scopes should be standardised enough for any used to find the right values to input without extensive guidance and prior knowledge.