Type checking in TableModel

[samtygier-stfc]

Issue

Some type checking for #2213

Description

This adds some type annotations to TableModel. This is slightly awkward because the data rows are a heterogenous list, and there is not way to strictly type its elements. We can't switch to a tuple, because they need to be mutable (maybe we can. but it is more code change).

So add ElementType and RowType, which limit the types, but don't understand the positions. and add an overloaded get_element() that fixes the type based on the literal value of the column argument.

Also some changes in the view to access things though get_element() and set_element()

Acceptance Criteria

Existing tests should all still pass
Play around with adding, removing and renaming ROIs

Documentation

Not needed

[coveralls]

coverage: 73.142% (-0.01%) from 73.156%
when pulling 1588106 on 2213-type-checking-2
into d407243 on main.

[coveralls]

coverage: 73.137% (-0.02%) from 73.156%
when pulling b9cc693 on 2213-type-checking-2
into 38eeb61 on main.

[JackEAllen]

Nice use of overloading