C-rate is not used in D1.storage_fix() only in D1.storage_optimize()

[SabineHaas]

As I understand from D1.storage_fix() here and here maximum discharge and charge possible in one time step for storage with fixed capacity. In contrast, for a storage with optimized cap (D1.storage_optimize() a c-rate can be given, see here. (From the Oemof.solph documentation I also only see the usage of a c-rate for investment optimization.) Is this right and is this how it should be in MVS?

Originally posted by @SabineHaas in https://github.com/rl-institut/multi-vector-simulator/issues/794#issuecomment-777636171

[smartie2076]

@SabineHaas @ciaradunks maybe you can also dicuss this one, at least the oemof side of this?