Handle dates specifically

[Yopai]

Hi,

=== Context
Phinx :) for this work.

I'm writing an Adapter for PDO-OCI.

I'm getting blocked by some things that should be fixed in.

=== Observed behaviour
The PDOAdapter generates the query with date formatted as string. Oracle generates an ORA-01843 error (invalid month).
Setting NLS_DATE_FORMAT has no effect (it may be related to the Oracle version)

== Proposed behaviour
As done for boolean, use a "castDate" method. Which would, for others, use the string as is. And could be overriden in OCIAdapter to encapsulate the string in a "TO_DATE".

Another way to do it, probably better, would be used parametrized queries.

(For now, I have overriden the migrated method in OCI-Adapter, I will push a PR when I'll find some time)