Add docker image for redis with ssl [2/3]

[Lagovas]

Here I added a new docker image for redis with ssl using pre-generated certificates. Also updated script that generates them and placed certs in tests/ssl as all other certs. Also, deleted redundant logs file previously erroneously added. This PR doesn't touch any Acra's functionality and is intermediate for next PR which will add tls support for redis. And splitted to simplify reviewing step-by-step.

After creating new image repository and getting rights on our hub.docker.com, I will push new image. P.S. this PR merges into #564 because it is intermediate for the next and last PR depends on #564 and this too. So, this PR will be merged after #564. And after merging last one, target branch will be changed to master.

Checklist

• [ ] Change is covered by automated tests
• [ ] The coding guidelines are followed
• [ ] Public API has proper documentation in the Acra documentation site or has PR on documentation repository with new changes
• [ ] CHANGELOG.md is updated (in case of notable or breaking changes)
• [ ] CHANGELOG_DEV.md is updated
• [ ] Benchmark results are attached (if applicable)
• are up-to-date (in case of API changes)