[LOW-869] Enable linting

This MR is to enable linting in the repository, disable linting by warning type on a per-file basis, and perform any simple linting improvements that can be immediately done. Further linting improvements can be done in new tickets. There is a standard method of warning suppression used which is by having a cell at the top of the notebook with each warning suppression on a new line.

Additionally this MR deletes the Initialise notebook that was autogenerated by Papermill.