UpdateBuilders should differentiate tables/collections for $push (and maybe more)

[sl-at-ibm]

The syntax (and behaviour) of $push differs for tables and collections. This does not seem to be captured by the UpdateBuilders class, which lets you create unacceptable commands.

Reference fact sheet on $push:

Tables:
- can target lists,sets,maps
- Can use [k, v]] for a kv pair, or a one-key {k: v} object
- no $position admitted anywhere
- (need a filter, or the api will error)
- supports $each

Collections:
- There's no notion of set; and push cannot target "maps" (json objects)
- So it's only for LISTS
- It admits $position
- supports $each

Additionally

The current description for the Push method says, Add a value to a set at a specified position.. The improved scoping notwithstanding (below), this is problematic in itself as for sets the order is not supposed to count.

Moreover, internally the Push implementations become a one-item $each (a minor waste of bandwitdh, one might note. Not so critical but...)

Desired

(this holds for the pushEach as well. $each is supported on tables and collections alike.)

Separate filter builders for tables/collection in order to offer $position only for collections.
Also for typed collections only list types should admit push (with position)