Assess whether a generic kbase cell could be created

[ialarmedalien]

A number of the cell types under nbextensions/ have similar or identical functionality, with such functions as load_ipython_extension, initialise_extension, setupNotebook, setupCell, specialiseCell, etc. Assess whether it would be possible to create a base cell type to provide functionality shared by all kbase cell types to help reduce duplication in the kbase cell type code.

At the same time, the following should also be done:

• standardise the cell layout pattern
• standardise the cell metadata
• use the cell deletion messages that the appCell and bulkImportCell use
• remove the setupWorkspace function, which can be replaced by supplying the workspace ID from the runtime.
• ensure that icons are built using the same functions as the bulk and app cell use.