Add log enricher documentation

[saschagrunert]

What type of PR is this?

/kind documentation

What this PR does / why we need it:

This patch adds log enricher documentation to the installation and usage
guide. It also reformats the headers to align with the new content.

Which issue(s) this PR fixes:

None

Does this PR have test?

None

Special notes for your reviewer:

None

Does this PR introduce a user-facing change?

Added log enricher documentation to installation-usage.md.

[codecov-commenter]

Codecov Report

Merging #498 (b8ea519) into master (f454845) will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master     #498   +/-   ##
=======================================
  Coverage   38.25%   38.25%           
=======================================
  Files          23       23           
  Lines        1200     1200           
=======================================
  Hits          459      459           
  Misses        726      726           
  Partials       15       15           

[saschagrunert]

/test pull-security-profiles-operator-test-e2e

[k8s-ci-robot]

@saschagrunert: The following test failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
pull-security-profiles-operator-test-e2e	b8ea519	link	/test pull-security-profiles-operator-test-e2e

Full PR test history. Your PR dashboard. Please help us cut down on flakes by linking to an open issue when you hit one in your PR.

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[jhrozek]

/lgtm
the documentation reads well to me.

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: jhrozek, saschagrunert

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• OWNERS [saschagrunert]

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[jhrozek]

btw feel free to merge despite the test failing, there's no reason a patch for readme should be blocked by a test :-) (unless you want to debug the test...)