[DBAL-166] Default MySQL to UTF8/utf8_general_ci. Allow to set default table options from SchemaConfig.

Updated OCI8Connection parameter name in order to separate oracle pooling handling with oci8 persistent connections

Adding PDO::FETCH_COLUMN support to OCI8 fetchAll method using the fetch structure OCI_FETCHSTATEMENT_BY_COLUMN.

[DBAL-237] Fix bug when removing and adding an index on the same columns that may be part of a foreign key.

DDC-451 - GUID support through a specific GUID Type, SQL Server specific implementation all others fallback to Varchar fields, no automatic default value = new guid support yet.

Removed is_int check and converted both comparisons into equality comparisons when expanding list parameters.

[DBAL-220] Add support for Index flags and implement support for SQL Server CLUSTERED/NONCLUSTERED and MySQL FULLTEXT.

This is necessary because pdo_sqlsrv still has some little bugs that
prevent it from being used in all use-cases. Additionally only sqlsrv
can make use of the Azure federations features.