Add trim, trim_left, trim_right

[AdRiley]

trim(, what:Text=W/S, where:Location=..Both): trim whitespace () from both ends of the column. compatible with existing Enso function. Needs widget work.

Location uses Left, Right, Both enum - default Both.
trim_left(, what:Text=W/S): trim whitespace () from the start of the column.

trim_right(, what:Text=W/S): trim whitespace () from the end of the column.