feat(patterns): add multi map

[0xRezaa]

This PR adds a Data-structure to the patterns package called MultiMap (similar to already existing SetMultiMap).

It maps key pairs to values
(k1, k2) -> v

@example

const m = new MultiMap([['a', 1, 'one'],['a', 2, 'two'])
m.add('a', 3, 'three')

m.has('a', 1) // => true
m.has('a',2) // => true
m.has('a',3) // => true
m.has('a',4) // => false

m.get('a', 1) // => 'one'
m.get('a',2) // => 'two'
m.get('a',3) // => 'three'
m.get('a',4) // => undefined

m.delete('a', 1) // => true
m.has('a', 1) // => false

This PR also refactors the SetMultiMap to use the MultiMap internally.
The SetMultiMap acts as a Set on key value pairs.
So we can conceptually see it as following MultiMap:
(k, v) -> boolean

[danieleww]

use unknown instead of any