Rename "service overview" to "service inventory" (elastic#81933)

To remove confusion when implementing elastic#81718, rename the existing "service overview" to "service inventory."

* Rename `ServiceOverviewLink` to `ServiceInventoryLink`
* Remove service inventory test snapshots
* Rename `ServiceOverview` to `ServiceInventory`
* Add `service_inventory` to pageview tracking
* Rename i18n keys for service inventory
* Change "return to overview" link to "return to inventory" on settings page
* Rename `fetchOverviewPageData` to `fetchObservabilityOverviewPageData`

x-pack/plugins/apm/e2e/cypress/support/step_definitions/apm.ts

@@ -11,7 +11,7 @@ import { loginAndWaitForPage } from '../../integration/helpers';
 export const DEFAULT_TIMEOUT = 60 * 1000;
 
 Given(`a user browses the APM UI application`, () => {
-  // open service overview page
+  // Open service inventory page
   loginAndWaitForPage(`/app/apm/services`, {
     from: '2020-06-01T14:59:32.686Z',
     to: '2020-06-16T16:59:36.219Z',

x-pack/plugins/apm/e2e/cypress/support/step_definitions/csm/csm_dashboard.ts

@@ -12,7 +12,7 @@ import { verifyClientMetrics } from './client_metrics_helper';
 export const DEFAULT_TIMEOUT = { timeout: 60 * 1000 };
 
 Given(`a user browses the APM UI application for RUM Data`, () => {
-  // open service overview page
+  // Open UX landing page
   const RANGE_FROM = 'now-24h';
   const RANGE_TO = 'now';
   loginAndWaitForPage(

x-pack/plugins/apm/public/components/app/Home/index.tsx

@@ -20,12 +20,12 @@ import { ApmHeader } from '../../shared/ApmHeader';
 import { EuiTabLink } from '../../shared/EuiTabLink';
 import { AnomalyDetectionSetupLink } from '../../shared/Links/apm/AnomalyDetectionSetupLink';
 import { ServiceMapLink } from '../../shared/Links/apm/ServiceMapLink';
-import { ServiceOverviewLink } from '../../shared/Links/apm/ServiceOverviewLink';
+import { ServiceInventoryLink } from '../../shared/Links/apm/service_inventory_link';
 import { SettingsLink } from '../../shared/Links/apm/SettingsLink';
 import { TraceOverviewLink } from '../../shared/Links/apm/TraceOverviewLink';
 import { SetupInstructionsLink } from '../../shared/Links/SetupInstructionsLink';
 import { ServiceMap } from '../ServiceMap';
-import { ServiceOverview } from '../ServiceOverview';
+import { ServiceInventory } from '../service_inventory';
 import { TraceOverview } from '../TraceOverview';
 import { AlertingPopoverAndFlyout } from './alerting_popover_flyout';
 
@@ -37,13 +37,13 @@ function getHomeTabs({
   const homeTabs = [
     {
       link: (
-        <ServiceOverviewLink>
+        <ServiceInventoryLink>
           {i18n.translate('xpack.apm.home.servicesTabLabel', {
             defaultMessage: 'Services',
           })}
-        </ServiceOverviewLink>
+        </ServiceInventoryLink>
       ),
-      render: () => <ServiceOverview />,
+      render: () => <ServiceInventory />,
       name: 'services',
     },
     {