Support a way to accurately express less than and greater than filters

[jgomer2001]

I found an issue when handling multivalued attributes in CB. It seems that strict inequality (<, >) filters cannot be accurately defined by reusing <=, >=, =, !

Example:

If chimp is a custom multivalued attribute and I want to query entries where chimp > 0 one thinks of using:

Filter.createANDFilter(
	Filter.createNOTFilter(Filter.createEqualityFilter(chimp, 0).multiValued(true)),
        Filter.createGreaterOrEqualFilter(chimp, 0).multiValued(true)
)

which produces

( objectClass = "gluuPerson" ) AND ( ( NOT 0 IN chimpn ) AND ANY chimpn_ IN chimpn SATISFIES chimpn_ >= 0 END )

If my data looks like

user1 = {
   "chimp": [0,1],
   ...
}

user2 = {
   "chimp": [1,2],
   ...
}

execution of the query only outputs user2 and rejects user1 because it contains 0.

I propose to add createGreaterFilter and createLessFilter methods to Filter interface and delegate converters the task of building the appropriate expressions.