Feature/eso patch

[EldarShalev]

I've implemented the ESO (External Secrets Operator) CRDs collection following the same minimal pattern as the ConfigMaps feature #769 .

Here's what was done:
Files Modified:
deploy/charts/disco-agent/templates/configmap.yaml
Added two new k8s-dynamic data gatherers:
ark/externalsecrets (group: external-secrets.io, version: v1, resource: externalsecrets)
ark/secretstores (group: external-secrets.io, version: v1, resource: secretstores)
No label selectors used (Option A: collect all in watched namespaces)

deploy/charts/disco-agent/tests/snapshot/configmap_test.yaml.snap
Updated all 4 test snapshot sections to include both ESO gatherers

examples/machinehub.yaml
Added both ESO gatherers with comments explaining their purpose

examples/machinehub/input.json
Added empty items entries for both ark/externalsecrets and ark/secretstores

internal/cyberark/dataupload/dataupload.go
Added ExternalSecrets []runtime.Object and SecretStores []runtime.Object fields to the Snapshot struct

pkg/client/client_cyberark.go
Added extractor functions for ark/externalsecrets and ark/secretstores

pkg/client/client_cyberark_test.go
Added both gatherers to defaultDynamicDatagathererNames list

pkg/client/client_cyberark_convertdatareadings_test.go
Added TestConvertDataReadings_ExternalSecrets test
Added TestConvertDataReadings_SecretStores test
Both tests verify: 2 resources are extracted, deleted resources are excluded
Files Created:
hack/ark/external-secret.yaml
Sample ExternalSecret CR for e2e testing (uses fake backend)
hack/ark/secret-store.yaml
Sample SecretStore CR for e2e testing (uses fake provider)
hack/ark/test-e2e.sh
Updated to apply both ESO sample manifests (with fallback if CRDs not installed)