Add default parameter loader's values to specific parameters

[vidaldid-rte]

NOTE: still in draft. Need to be tested in other repos that provide default parameter implementations.

Please check if the PR fulfills these requirements

• The commit message follows our guidelines
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)
• A PR or issue has been opened in all impacted repositories (if any)

Does this PR already have an issue describing the problem?
No

What kind of change does this PR introduce?
LoadFlowProvider.getSpecificParameters does not set the default values of a LoadFlowDefaultParameterLoader

What is the new behavior (if this is a feature change)?

• getSpecificParameters overrides the raw specific parameters with values from the LoadFlowDefaultParameterLoader if present
• The getSpecificParameters with a PlatformConfig overrides the values that take into account the default loadflow parameter loader if present in the classpath

IMPORTANT: the loadFlowProvider implementations must rename getSpecificParameters to getRawSpscificParameters
See example in powsybl/powsybl-open-loadflow#1299

Additionally , tests have been updated:
to align default values of DummyExtension with the defautl of the provider
to cover the case of a String List parameter (wich is nullable, to reflect the case of OuterLoopNames in OpenLoadFlow)

Does this PR introduce a breaking change or deprecate an API?

• [X ] Yes
• [] No

LoadFlowProviders should now implement getRawSpecificParameters (new method) instead of getSpecificParameters.

getSpecificParameters is now meant to override values if a default loadflow parameter loader is available. The default implementation of the LoadFlowProvider interface honnors the contract and is based on getRawSpecifciParameters.

LoadFlowProvider impementation can just remname their old method getSpecificParameters to getRawSpecificParameters

[sonarqubecloud]

Quality Gate passed

Issues
1 New issue
0 Accepted issues

Measures
0 Security Hotspots
95.6% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud