Add page describing data types of labels layers and their implications

[jni]

📚 New content request

While discussing napari/napari#6695 in the PR party we noted that users might not know the implications of that setting, and in general the implications of using different data types for the labels layers. Specifically:

• the bit depth determines the memory usage, and can result in an 8x difference in RAM usage
• in napari in particular, uint8 and uint16 have much better performance when slicing/refreshing because of implementation details
• but bit depth also limits the maximum label number

Once this page is done, ideally, we would add a link to it in the description of the new labels dtype preference.