Create the new variables and constraints for the multi-year investment for storage (i.e., vintage)

[datejada]

• [ ] Create the vintage variables and constraints, but don't link them to the current variables
• [ ] Create the tests for the new variables and constraints

This issue is only for the storage. The changes for units are in #911 and for connections are in #977

Don't change the objective function yet; this will be covered in #912

[datejada]

Changes in the code are available in the following discussion: https://github.com/spine-tools/SpineOpt.jl/discussions/476

[datejada]

Close in favour of implementing the multi-year investment through data; see las comment #476