Corrected error codes expected from Mssqlex for storage up and down

[jbachhardie]

Description

Made the adapter translate the error codes from Mssqlex so that tools like mix ecto.create can tell when a command failed due to the database already being up and not error.

Motivation and Context

Should close https://github.com/findmypast-oss/mssql_ecto/issues/8

How Has This Been Tested?

All tests passing. Manually tested with a new test phoenix project as described in https://github.com/findmypast-oss/mssql_ecto/issues/8

Types of changes

• [X] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [X] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [X] All new and existing tests passed.