[Index Management] Implement index details page (#165705)

## Summary
This PR removes the feature flag and enables the new index details page
by default. The index details page was implemented in following PRs:
- https://github.com/elastic/kibana/pull/163521
- https://github.com/elastic/kibana/pull/163955
- https://github.com/elastic/kibana/pull/164741
- https://github.com/elastic/kibana/pull/165027
- https://github.com/elastic/kibana/pull/165038
- https://github.com/elastic/kibana/pull/165456

In this PR we completely remove now obsolete code for the old index
details flyout: react components and corresponding redux code. All
related tests are updated and cleaned up. The config value for Index
Management plugin `xpack.index_management.dev.enableIndexDetailsPage` is
deprecated as unused and can be removed in v9.0.


### How to test
1. Start ES and Kibana with `yarn es snapshot` and `yarn start`
3. Navigate to Index Management and create an index
4. Click the index name in the table and check the tabs of the details
page
### Screenshots
#### Stateful
Overview 
<img width="1387" alt="Screenshot 2023-09-27 at 14 41 57"
src="e58b15e7-d10c-4473-873c-d0f128392404">


Mappings
<img width="1392" alt="Screenshot 2023-09-27 at 14 42 05"
src="441157cb-5a26-47c3-8da0-b4df51ebec5d">


Settings 
<img width="1385" alt="Screenshot 2023-09-27 at 14 42 13"
src="da66a2eb-1f21-44c1-9356-484c66caab88">


Statistics
<img width="1380" alt="Screenshot 2023-09-27 at 14 42 22"
src="ec93d85c-e754-4c21-88ab-0124dc114fc9">


Error loading data
<img width="1333" alt="Screenshot 2023-09-26 at 19 05 37"
src="fc1804b3-6aa0-4019-bae6-e7bb40113b28">
<img width="1327" alt="Screenshot 2023-09-26 at 19 06 07"
src="ca711697-cc74-4ba8-b17c-ec9b01f3026e">
<img width="1329" alt="Screenshot 2023-09-26 at 19 06 28"
src="0cb46b09-8542-452a-8845-40d060057e95">
<img width="1331" alt="Screenshot 2023-09-26 at 19 06 48"
src="87de8d3d-b6e5-4e8f-b27c-18a1c6e950d8">


Error saving index settings
<img width="1332" alt="Screenshot 2023-09-26 at 19 07 31"
src="e6e4b3d0-c237-4d0a-995a-4562bc78f88e">


### Serverless
Overview 
<img width="1336" alt="Screenshot 2023-09-26 at 19 51 47"
src="6c76c23b-4be6-4ab3-ae1d-c7ae751e100d">


Mappings
<img width="1336" alt="Screenshot 2023-09-26 at 19 23 51"
src="625fa703-506f-4389-9df0-86441a655074">


Settings
<img width="1332" alt="Screenshot 2023-09-26 at 19 24 02"
src="c496ab09-f2db-4c1b-9fb6-1e9b64b1c142">


# Release note
Index details can now be viewed on a new index details page in Index
Management.
<img width="1387" alt="Screenshot 2023-09-27 at 14 41 57"
src="b90c706d-8b15-49e4-8f6a-cb66f3ed1822">

---------

Co-authored-by: kibanamachine <42973632+kibanamachine@users.noreply.github.com>

test/plugin_functional/test_suites/core_plugins/rendering.ts

@@ -247,7 +247,6 @@ export default function ({ getService }: PluginFunctionalProviderContext) {
         'xpack.index_management.ui.enabled (boolean)',
         'xpack.index_management.enableIndexActions (any)',
         'xpack.index_management.enableLegacyTemplates (any)',
-        'xpack.index_management.dev.enableIndexDetailsPage (boolean)',
         'xpack.index_management.enableIndexStats (any)',
         'xpack.infra.sources.default.fields.message (array)',
         'xpack.license_management.ui.enabled (boolean)',