Add Embedded Document Support to Aliasing

[durran]

See mongoid/mongoid#2361

We can allow Origin to look at operations with a . in them, and check for aliases under a fully embedded tree... For example:

# In the provided aliases:
{ "addresses" => { "name" => "n" }}

# Then the query could alias "name" to "n":
queryable.where("addresses.name" => "Köpenicker Landstraße")