Provide some guidance in the docs about TiledDiskArray vs ConcatDiskArray

[meggart]

Now that we have both ConcatDiskArray and TiledDiskArray in relatively good shape, there are 2 slightly different strategies for building large diskarrays from mosaics of smaller ones.

1. Using TiledDiskArrays where each a generator function loads the tile, which is a chunk in memory needed. Convenient for lazily loaded data where chunks can be addressed like in a TileServer
2. Using ConcatDiskArray used for concatenation of already instantiated DiskArrays that might be large and chunked themselves.

We should add a paragraph to the Readme/docs describing the strategies with 1-2 examples. Can be agent-generated.