Variable Explorer issues

[juanis2112]

• Fix default width of columns to avoid disappearing names of them
• Add tooltip when complete names are not visible in collapsed columns (name, type, size, variable names)
• Move resizing columns and rows from context menu to options menu
• Remove show max/min from context menu
• Add Filter button to activate/deactivate the filters for the variables. (Unchecked Checked by default. See PR: Improve Variable Explorer UX spyder#20868 (comment))
• Add "edit filters" option in the context menu to edit the filters, which goes to preferences.
  - [ ] In the edit filters option in preferences the options currently activated by defaullt should still be checked by default. See PR: Improve Variable Explorer UX spyder#20868 (comment)

[ccordoba12]

I have a couple of additional suggestions to make it discoverable that the Variable Explorer entries are clickable and can open additional viewers for different variable types:

1. Change the mouse shape to Qt.PointingHandCursor when hovering the Variable Explorer.
2. Make that a single mouse click open our viewers for Dataframes, Numpy arrays, etc.