ddev logs -s db should provide the info in /var/log/mysqld.log

[rfay]

Describe the bug

Currently you have to docker commit and then docker run -it <commit_id> bash and then docker exec to examine the mysqld.log for a broken db container.

Instead, mysqld should be outputting this stuff to stdout or stderr where docker logs and ddev logs -s db will have access to it.

To Reproduce

• Break a db (see Improve ddev failure time when start isn't working out #1135)
• Start the project
• ddev logs -s db does not explain the problem.

Expected behavior

We should see fatal errors in ddev logs -s db

Screenshots
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Version and configuration information (please complete the following information):

• Host computer OS and Version: [e.g. Windows 10, macOS High Sierra]
• Docker version information (use docker version) and insert it here.
• ddev version information (use ddev version)
• config.yaml contents for the misbehaving project
• Do you have any custom configuration (nginx, php, mysql) in the .ddev folder? If so, have you tried without them?

Additional context
Add any other context about the problem here. Thanks!