Specify purpose of GLSK file

[bqth29]

Describe the current behavior

Only one method set_glsk_file_source exists.

Describe the expected behavior

The method set_glsk_file_source should be splitted in two methods:

• set_loopflow_glsk_file_source used for loopflow computations in flow RAO
• set_monitoring_glsk_file_source used for redispatching in angle monitoring

Describe the motivation

No response

Extra Information

In OpenRAO, this distinction is made through the input object given to the RAO.

• for loop flow GLSKs (ZonalData<SensitivityVariableSet>), the GLSKs are given to the RaoInput used in the flow RAO and thus interpreted as loopflow GLSKs
• for redispatching GLSKs (ZonalData<Scalable>), the GLSKs are given to the MonitoringInput used in the angle/voltage monitoring

In pypowsybl, we could use two different GLSKs object and provide each one to its associated computation engine.

[obrix]

Fixed by #1126