Extract the common type definitions for microscopy into a new package

[kunzaatko]

We use Frequency and perhaps in the future SampledArray in both this and SIMIlluminationPatterns, but it would be
useful to be able to include these types without requiring this package as a dependency. For instance,
SIMReconstuctions can use SampledArray without specifically requiring the TransferFunctions as a direct dependency.
A new parent package should be created that defines these types.