Enable certificate validation for LDAPS connections

### Current Behavior

When using ldaps, the certificate of the ldaps connection is just always accepted.

### Proposed Behavior

When using ldaps, the certificate of the ldaps connection should be validated with the certificate store.

### Checklist

- [x] I have read and understand the [contributing guidelines](https://github.com/DependencyTrack/dependency-track/blob/master/CONTRIBUTING.md#filing-issues)
- [x] I have checked the [existing issues](https://github.com/DependencyTrack/dependency-track/issues) for whether this enhancement was already requested