fix(zql): Fix type of IN/LIKE operators

[arv]

The RHS of IN needs to be an array
The RHS of LIKE/ILIKE needs to be a string

[arv]

I decided to not allow undefined in these cases.

I guess it could be argued that we should allow it for = and !=?

[arv]

I think we should think about what we want here when it comes to representing optional values in PSQPL.

[tantaman]

null is another thing we need to think about. Unfortunately SQL has odd rules around null when it comes to equality.

sqlite> create table foo (a);
sqlite> insert into foo values (null);
sqlite> .mode qbox
sqlite> select * from foo;
┌──────┐
│  a   │
├──────┤
│ NULL │
└──────┘
sqlite> select * from foo where a = null;
sqlite> select * from foo where a != null;
sqlite> select * from foo where a IS null;
┌──────┐
│  a   │
├──────┤
│ NULL │
└──────┘
sqlite> select * from foo where a IS NOT null;
sqlite>
sqlite> insert into foo values (1);
sqlite> select * from foo where a != null;
sqlite> select * from foo;
┌──────┐
│  a   │
├──────┤
│ NULL │
│ 1    │
└──────┘