Add OracleDB support to golang-migrate

[JailtonJunior94]

Add OracleDB support to golang-migrate
This PR implements support for OracleDB in golang-migrate. The main changes include:

• Addition of the OracleDB driver in oracle.
• Implementation of necessary functions for migrations, including Open, Close, Lock, Unlock, Run, SetVersion, Version, and Drop.
• Addition of tests for the OracleDB driver in oracle_test.go.
• Update of the documentation in README.md to include instructions on how to use the OracleDB driver.

How to Test:

1. Set up an OracleDB environment.
2. Run the unit and integration tests to ensure all functionalities are working correctly.
3. Follow the instructions in the documentation to test real migrations using the OracleDB driver.

[coveralls]

coverage: 57.043% (+0.7%) from 56.319%
when pulling a601110 on JailtonJunior94:oracle
into d477553 on golang-migrate:master.