feat: require log levels in driver config

[LayZeeDK]

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[ ] Bugfix
[x] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Other... Please describe:

What is the current behavior?

1. The levels property of a log driver config is optional.
2. The default log driver config has an undefined levels property.

Issue Number: N/A

What is the new behavior?

1. The levels property of a log driver config is required.
2. The default log driver config has Verbose log level.

Does this PR introduce a breaking change?

[x] Yes
[ ] No

Both points described in new behavior.

Other information

[LayZeeDK]

The HTTP driver module needs an option to inherit log levels from the root log driver config.

[LayZeeDK]

@NachoVazquez what do you think about commit 7439290?

[LayZeeDK]

Rebased on top of LayZeeDK/test/fix-wallaby-and-driver-tests.