feat: support like operator

- Support like operator with signature:

expr1 LIKE expr2 [ESCAPE expr3]

which returns TRUE only if expr1 matches the
string specified by expr2 (pattern). '_' in
pattern matches any single character, '%'
matches any character 0 or more times. All
other characters match itself according to
case.

- Optional escape clause specifies character
to use for escaping '_' and '%'