lisa: Remove matplotlib dependency
Pending on: https://github.com/holoviz/holoviews/pull/6196
If that gets merged, then we can leave the matplotlib-related options() as they are, and even simplify some other code in LISA that checks what is the Store.current_backend before setting options.
FEATURE
Remove matplotlib as a hard dependency. This provides a significant import speedup as matplotlib initialization is quite costly, and it's not really used anymore anyway.
Edited by Douglas Raillard