Refactor Apache/Nginx auto-instrumentation init containers

[movence]

Issue #, if available:
Apache/Nginx auto-instrumentation init containers built their command line by concatenating user-supplied configuration paths into a shell string, and the corresponding CRD fields had no character or length constraints.

Description of changes:
Cherry-picks the upstream init container refactor from opentelemetry-operator (PR #4942, v0.151.0) and regenerates the Instrumentation CRD.

• Move init container logic from inline shell strings to embedded scripts under pkg/instrumentation/scripts/, invoked with positional arguments
• Add length and pattern validation to Instrumentation.spec.{apacheHttpd.configPath, nginx.configFile}
• Regenerate CRDs via make manifests

Tests

Component	Test	Result
pkg/instrumentation/{apachehttpd,nginx}.go + scripts/*.sh	Runtime check on init container Command/Args shape — confirmed positional argument layout	✅ Pass
pkg/instrumentation/{apachehttpd,nginx}.go + scripts/*.sh	Shell semantics check — script body executed as expected with the user-supplied value as $1	✅ Pass
apis/v1alpha1/instrumentation_types.go (new pattern marker)	make manifests regenerated CRD with the marker propagated	✅ Pass
config/crd/bases/cloudwatch.aws.amazon.com_instrumentations.yaml	kind cluster + kubectl apply --dry-run=server: 4 inputs containing disallowed characters rejected, 2 standard paths accepted	✅ 6/6
Build	go build ./..., go vet ./...	✅ Pass

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