Edited Feature: Collections support [2]

type declaration:

```
type CollectionOfStrings = System.String[]
```

usage (see ModularEngine/samples/MultiMain/collections.mdkal):

```
relation rel(A: CollectionOfStrings)

knows rel(["qwe"; "asd"; "zxc"])
knows rel([])

with A: CollectionOfStrings
if rel(A) && asInfon({|"basic"|A.exists("qwe")|})
do send to me: rel(A)

if rel(A) && asInfon({|"basic"|A.isEmpty()|})
do send to me: log("empty") && rel(A)
```