docs: Add docs for unmanaging modules #2671

Job	Run time
Build Image / compute-tag	6s
Build Image / build-image / Build image	5m 9s
E2E (watcher-enqueue)	4m 28s
E2E (kyma-deprovision-with-foreground-propagation)	5m 26s
E2E (kyma-deprovision-with-background-propagation)	5m 15s
E2E (module-status-decoupling-with-statefulset)	6m 40s
E2E (module-status-decoupling-with-deployment)	17m 16s
E2E (kyma-metrics)	6m 8s
E2E (module-without-default-cr)	5m 4s
E2E (module-consistency)	10m 10s
E2E (non-blocking-deletion)	10m 39s
E2E (upgrade-under-deletion)	10m 16s
E2E (purge-controller)	4m 48s
E2E (purge-metrics)	4m 49s
E2E (module-upgrade-channel-switch)	5m 20s
E2E (module-upgrade-new-version)	6m 2s
E2E (unmanage-module)	7m 5s
E2E (module-install-by-version)	4m 10s
E2E (skip-manifest-reconciliation)	6m 28s
E2E (ca-certificate-rotation)	4m 47s
E2E (self-signed-certificate-rotation)	5m 25s
E2E (mandatory-module)	6m 56s
E2E (mandatory-module-metrics)	4m 12s
E2E (misconfigured-kyma-secret)	4m 24s
E2E (rbac-privileges)	3m 2s
E2E (ocm-compatible-module-template)	5m 7s
	2h 39m 12s

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