Change Oracle sequence generation to match what is being created by ORM and other platforms in the form of $table_$column_SQL instead of $table_SEQ

Choose between TINYBLOB, BLOB, MEDIUMBLOB and LONGBLOB based on the length of the field.
Behaves the same way as the TEXT type declaration.

This should be 65535 (2 ^ 16 - 1) in stead of 65532.
Modified docblock to show the max lengths.