Support regex expressions

[jaychia]

Is your feature request related to a problem? Please describe.

Support working with strings with regex expressions. The Ibis docs link 4 useful features:

re_extract Return the specified match at index from a regex pattern.
re_replace Replace all matches found by regex pattern with replacement.
re_search Return whether the values match pattern.
re_split Split a string by a regular expression pattern.

[ghalimi]

When you add support for re_split, please make sure that you provide support for parentheses in order to preserve the separators.