Create LayerFactory and ComponentStore from common class

[marksgraham]

Is your feature request related to a problem? Please describe.
There are similarities between the LayerFactory and newly implemented ComponentStore (see this PR) - both are factories, one for objects, one for functions.

Describe the solution you'd like
We've decided to create a common Factory class these two inherit from.

Describe alternatives you've considered
It is also possible to use LayerFactory for both cases, but would require giving it a more generic name and this would mean we would have to deprecate LayerFactory.

Additional context
Add any other context or screenshots about the feature request here.