Update instructions for C++ BSK modules to use setters and getters

[schaubh]

• Tickets addressed: bsk-715
• Review: By commit
• Merge strategy: Merge (no squash)

Description

The C++ Basilisk module variables were often public variables, sometimes private variables with setter and getter methods.
From here on the expectation is that C++ module variables are private and accessed via set and get commands.

The makeDraftModule.py, module writing instructions and tutorial lessons need updating.

The logger() function right now only logs public module variables. This method needs to be updated to allow both public variables and variables accessible via get functions to be logged.

Verification

All unit tests pass again.

Documentation

Updated all associated documentation, tutorials, sample scripts and C++ template module documentation.

Future work

None

[Mark2000]

A couple of style comments. Don't know enough about swig to weigh in on those aspects, but it seems right to me.