this removes create_panel function from panels and mandates a class name Panel
remove panel_type param and only use a panel_name that is it's filename
remove load_panel dict
always reinit panel, (simpler and safer but slower)
Use f-strings
Avoid unnecessary casts to str()bool()int()
Ensure file closure
Merge nested ifs
Simplify for-assigns-appends with comprehensions and internal functions
Avoid shadowing internal function names
Initialize variables
Return value directly instead of assign then return
Make some methods static
