Update EIM API description (#398)

* Update EIM API description
* Fix lint

Author: jkossak

docs/api/edge_infra_manager.rst

@@ -7,6 +7,12 @@ Update, Delete capabilities for all the Edge Infrastructure Manager elements:
 sites, regions, hosts, OS profiles and Resources, workloads, instances,
 provides, Telemetry configuration, Maintenance Schedules and more.
 
+Depending on the EIM scenario, some of the APIs may not be supported. Currently EIM API supports the following scenarios:
+
+- Full EIM - all APIs are supported.
+- EIM vPRO - only a subset of APIs is supported for vPRO feature management, limited to Create, Read, Update, and Delete operations for hosts.
+- EIM without Observability - all EIM APIs are supported except observability-related APIs, such as Telemetry configuration.
+
 The APIs return error codes based on the internal result of the operation.
 
 Edge Infrastructure Manager REST API are secured via certificates and