Configurable log level/format for gardener-resource-manager

[oliver-goetz]

How to categorize this PR?

/area control-plane
/kind enhancement

What this PR does / why we need it:
This PR creates cli parameters --log-level=<debug/info/error> and --log-format=<json/text> in gardener-resource-manager and enables their configuration in gardener-control-plane helm chart and botanist package.
The later does not include a dedicated configuration for gardener-resource-manager and this PR does not create one for this purpose only. This is the log-level/format configurations:

When running on Seed clusters:
log-level and log-format settings of gardenlet are used for gardener-controller-manager too

When running on Shoot clusters:
There are default values only --log-level=info --log-format=json

In both scenarios different log-levels/format could be set by changing their deployments while ignoring the corresponding managed resource during reconciliation.

Which issue(s) this PR fixes:
Part of #5191

Special notes for your reviewer:
This PR adds a verification of log-levels and log-format for gardener-apiserver which was forgotten in #6817

Release note:

log-level and log-format of gardener-resource-manager can now be configured.

[gardener-prow]

@oliver-goetz: The following tests failed, say /retest to rerun all failed tests or /retest-required to rerun all mandatory failed tests:

Test name	Commit	Details	Required	Rerun command
pull-gardener-check-vulnerabilities	20d0930	link	false	/test pull-gardener-check-vulnerabilities
pull-gardener-e2e-kind-ha-single-zone	20d0930	link	false	/test pull-gardener-e2e-kind-ha-single-zone
pull-gardener-e2e-kind-ha-multi-zone	20d0930	link	false	/test pull-gardener-e2e-kind-ha-multi-zone
pull-dependency-watchdog-verify-image-build	20d0930	link	true	/test pull-dependency-watchdog-verify-image-build

Full PR test history. Your PR dashboard. Command help for this repository.
Please help us cut down on flakes by linking this test failure to an open flake report or filing a new flake report if you can't find an existing one. Also see our testing guideline for how to avoid and hunt flakes.

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[rfranzke]

Same here for GRM

2022-10-13T18:13:19.465917487Z stderr F Error: unknown flag: --log-level
2022-10-13T18:13:19.466001249Z stderr F {"level":"error","ts":"2022-10-13T18:13:19.465Z","msg":"Error executing the main controller command","error":"unknown flag: --log-level","stacktrace":"main.main\n\t/go/src/github.com/gardener/gardener/cmd/gardener-resource-manager/main.go:35\nruntime.main\n\t/usr/local/go/src/runtime/proc.go:250"}

[oliver-goetz]

This seems to be an issue with the HA e2e tests. They do not use the local built gardener-core images, but the latest dev version from eu.gcr.io

• HA single zone e2e test: images.log
• normal e2e test: images.log

[oliver-goetz]

Ahhh I see, the image vector overwrites are not set for HA e2e tests in skaffold.yaml
I will fix this in a separate PR.

[rfranzke]

Awesome, thanks @oliver-goetz for checking!

[rfranzke]

/lgtm
/approve

[gardener-prow]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: rfranzke

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