Uniform comment structure throughout the codebase

[ccarels]

Description
A uniform consistent comment structure is needed throughout.

In order to make a start and to facilitate developers adding comments, empty templates can be added throughout the code, to be filled in with details as time goes on.

Outcome
A basic structure for making comments in the code.

To include methods and functions, as well as variables, and elsewhere as needed.

Comments should be Doxygen compatible.

Timeline
As soon as possible.

Interfaces
Will this feature result in a backwards-incompatible interface change: No.

Expected semantic version number increment category (Please indicate x.y.z): y.

Notes
N/A.

[ccarels]

Subsumed under cc_pipeline_interfaces.