Renaming (multi rename): mask -> add regex

[t3ster]

1)
Add a regex option in the leftside, mask part.

Example:
[N3-] In the multi-rename dialog in the topleft combobox/dropdownlistbox removes the first 3 characters.
Add an regex inputfield above that topleft combobox/dropdownlistbox in which the user can enter an regex.
This would result in everything that matches that regex will have the [N3-] mask applied (first 3 letters removed).

regex inputfield above the topleft [N] combobox/dropdownlistbox
Image: https://static1.howtogeekimages.com/wordpress/wp-content/uploads/2011/03/image107.png

2)
Optionally:
Regarding above first request, maybe add a way to target the column (Size, Date, Location,...).
Location is useful when searched for file/folders and then did a 'feed to listbox' and does selects all and does [CTRL]+[M]
Example, again [N3-] but now with a regex as explained above but that regex targets the 'Location'