Add adal4j to support active directory authentication

[legiangthanh]

mssql-jdbc will dynamically load the ada4j library when authentication is ActiveDirectoryPassword. But currently, the gem's classpath doesn't contain the ada4j library, mssql-jdbc will throw an exception.

Caused by: com.microsoft.sqlserver.jdbc.SQLServerException: Failed to load ADAL4J Java library for performing ActiveDirectoryPassword authentication.
        at com.microsoft.sqlserver.jdbc.SQLServerConnection.validateAdalLibrary(SQLServerConnection.java:4233)

This PR will add the add4j library to the dependency of sqlserver to include this library in the gem's classpath.

[dmikurube]

It basically looks good, but can you leave an explicit technical background description in the PR description how "Just adding the adal4j library makes it support the ACtive Directory-based authentication"?

[dmikurube]

Thanks. Okay, the description looks reasonable.

[dmikurube]

@hito4t We're going to release this (for SQLServer) as 0.12.4, jfyi.