Refactoring of composite schedule calculation

[marcemmers]

Describe your changes

The main purpose of this change was to fix an issue discovered during testing with OCTT. The scenario:

• The CS has multiple EVSEs
• It has a ChargePointMaxProfile with a limit of 32A
• It has a TxDefaultProfile with a limit of 10A installed on evseId 0 (so this counts for all EVSEs)
• Getting a composite schedule for evseId 0 should then calculate the sum of the schedules for each evse and combine that with the ChargePointMaxProfile. This should result in a limit in the composite schedule of 20A.

Along the way I fixed another issue: Conversion between power and current was done to early resulting in issues especially when the number of phases was non default.

The bulk of the functionality to calculate the composite profile in profile.cpp has been split into several functions to make it easier to understand how the code is composed.

There are also still some gaps left in this code. We currently have default limits that are global, so the same for the whole charging station and EVSEs. It could be the case that different EVSEs have different default limits or that the CS has a higher limit (since it needs to support multiple EVSEs. This is something that will need to be added in a later PR.

Issue ticket number and link

Checklist before requesting a review

• I have performed a self-review of my code
• I have made corresponding changes to the documentation
• If OCPP 2.0.1: I have updated the OCPP 2.0.1 status document
• I read the contribution documentation and made sure that my changes meet its requirements

[marcemmers]

I have disabled a bunch of unit tests in test_profile.cpp. These are tests that were built on the old profile.cpp implementation. I would like to propose to remove them all together since it is testing implementation details which will already be tested by test_composite_schedule.cpp and potentially others

[james-ctc]

the approach looks good. I've not spotted any code issues.