Filter on recursion relationship

[DaniilAnichin]

In sqlalchemy ModelView, when having a model with self-join as relation(let's call it child), flask admin cannot filter over both child and child parent fields, since they're mapped to the single key_name in scaffold_filters method. However, all the needed joins are okay. When creating a query, both parent and child field refers to parent alias in raw sql(checked many times). Solution - add some part to the filter name, if there are joins already. Check PR pls #1618