[ANT-706] Add ST-storage (variant) commands

[laurent-laporte-pro]

Problem statement

The purpose of this request is to add the CreateSTStorage and RemoveSTStorage commands for creating and deleting short-term storage. These commands are needed to implement the entry points for this new object (#1522). They are used both for managing a study variant and for a RAW study.

Proposed solution

Create a new CreateSTStorage class which inherits from the ICommand class.

The attributes are :

• area_id: the unique identifier of the area containing this new short-term storage,
• storage_name: the name of the short-term storage,
• parameters: short-term storage configuration parameters (INI file),
• pmax_injection: the Pmax injection matrix (time series),
• pmax_withdrawal: Pmax withdrawal matrix (time series),
• lower_rule_curve: the min curve matrix (time series),
• upper_rule_curve: max curve matrix (time series),
• inflows: the inflows matrix (time series).

Create a new RemoveSTStorage class which inherits from the ICommand class.

Attributes are :

• area_id: the unique identifier of the area containing this new short-term storage,
• storage_id: the unique identifier of the short-term storage to be removed.