[5.8] Fix insertOrIgnore() and insertUsing() as Eloquent queries

[staudenmeir]

When being called as an Eloquent query, insertOrIgnore() and insertUsing() return the query builder instead of the actual result (number of affected rows / success):

User::insertOrIgnore(['foo' => 'bar']);

User::insertUsing(['foo'], "select 'bar'");

[tw99]

@staudenmeir With the addition of insertOrIgnore does that mean Laravel would accept a PR for upsert?

[staudenmeir]

@tw99 Please ask Taylor about that.