Add matchesPattern as a $filter function

Add matchesPattern as a $filter function:   Edm.Boolean matchesPattern(Edm.String,Edm.String)   The matchesPattern function returns true if the second parameter string value evaluates to a  [ECMAScript]  (JavaScript) regular expression and the result of the first argument string matches that regular expression, using syntax and semantics of  [ECMAScript]  regular expressions, otherwise it returns false.

https://github.com/oasis-tcs/odata-abnf/pull/8 https://www.oasis-open.org/committees/download.php/64118/odata-v4.01-wd06-part2-url-conventions-2018-10-19.docx https://www.oasis-open.org/committees/download.php/64119/odata-v4.01-wd06-part1-protocol-2018-10-19.docx