improvements for cert-base auth testing in CI

[mniestroj]

Add some improvements that allow to test cert-based auth in CI. This exact set of changes allowed to test qemu_x86 with cert-based authentication with self-hosted server in GitLab CI.

Following environment variables needed to be set per CI runner instance:

• GOLIOTH_SYSTEM_CLIENT_CA_PATH=path/to/server/ca
• GOLIOTH_SYSTEM_CLIENT_CRT_PATH=path/to/device/crt
• GOLIOTH_SYSTEM_CLIENT_KEY_PATH=path/to/device/key
• GOLIOTH_HOSTNAME_VERIFICATION_SKIP=y

With hosted (dev or prod) servers it will be enough to just set:

• GOLIOTH_SYSTEM_CLIENT_CRT_PATH=path/to/device/crt
• GOLIOTH_SYSTEM_CLIENT_KEY_PATH=path/to/device/key

or alternatively generate those during the CI run automatically per each test / CI job.

Depends on:

• 382

• 383

[github-actions[bot]]

Visit the preview URL for this PR (updated for commit 70e2be8):

https://golioth-zephyr-sdk-doxygen-dev--pr385-cert-based-auth-l4ygvkhi.web.app

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