Add support for ome pyramid (multi-resolution) files

[folterj]

Reverted multi-layer code to the original single layer using channel_axis.
Extended ome-tiff testing, with metadata and loading existing files, and testing napari layer/metadata.

[GenevieveBuckley]

Ok, I think we have too many ideas happening in one PR. I love that you have lots of improvements, but I think we're going to have to break this up into smaller chunks for make it easier for me to review and merge things.

Can we separate the pyramid support from the ome-tiff metadata handling?

[Czaki]

In general, the code looks good.

For me, the main problem is lack of descriptive comments under if comments to clarify some edge cases.
Also, code should contain direct raising exception not pass 4 colormaps for 5 channels.

Instead of providing default values for some parameters, like scale, blending etc I prefer to provide None here and allow the viewer to handle this (for example adjust scale to already added layers).

Maybe part of my comment are dumb because I do not have proper context.

[GenevieveBuckley]

Thank you so much for your contribution @folterj 🎉
This is a really helpful feature to have, especially as there are so many people out there working with multi-resolution files.

I'd also like to apologize to you for both the delay in getting this merged, and for the number of unrelated reviewer comments on this PR.