Feature: add array operators

[emmanuel]

Adds new contArr and intersectsArr query operators, with the intersectsArr operator generating SQL queries like:

select ... where tags::text[] && ARRAY[$1,$2];

This selects rows where the tags column, which is presumed to be of type text[], contains at least one value that equals $1 or $2.

Fixes #687

[emmanuel]

We currently use this patch on top of 4.6.2. I'd be happy to open a PR for 4.6.x, if someone will create a branch I can use as a PR target.

[andrewvasilchuk]

Thank you. Is this going to be merged?

[BenStirrup]

Good initiative and indeed welcomed feature !
@michaelyali when you have time, could you review it ?

[bestori]

A small question

[bestori]

Why is this block ($eq?:... to notinL) marked deleted? Looks like an indent issue with your code editor of choice...?

[bestori]

Please merge with main or close :O)

[afilp]

@emmanuel Hi, since this repo seems to be obsolete, can you please check the same PR code in the new (maintained) fork here?
gid-oss#19
gid-oss#21

If you wish I can delete my PR and you can create a new one there. (I created it there using your code because I was asked to)

Thanks a lot!