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 https://github.com/spyder-ide/spyder/pull/20868#discussion_r1215065240)
• [ ] 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 https://github.com/spyder-ide/spyder/pull/20868#discussion_r1216973873

[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.