Allow to optionally build default keys using table aliases

[yhabteab]

Currently the default keys are created based on the table names, we should also provide the ability to optionally specify whether to use the table alias (if any) instead.

[nilmerg]

This deviates from our current design where we expect that if no explicit foreign key or candidate key is defined for a relation, the default is inferred from the the related table's name. (host.id -> host_id)

If we change this, so that the default is inferred from the alias instead, this will be broken for anyone who relies on that and wants to use the alias for the sole purpose of having nice relation paths in filters.

$tableName = 'prefix_actual_name';
$tableAlias = 'actual_name';

CREATE TABLE prefix_related_name (
  prefix_actual_name_id int,
  ..
);

At this time, I'd rather require from anyone who's schema uses mixed naming (prefix in the table name, but not in foreign keys or no prefix in the table name, but in foreign keys) should be required to be explicit when defining relations, as it is now.