Cleanup install documentation (#951)

## Changes
This PR removes the gif showing old method of install UCX using
install.sh. Also updating the Readme to show the new method to install
Windows and added new image


### Functionality 

- [X] added relevant user documentation
- [ ] added new CLI command
- [ ] modified existing command: `databricks labs ucx ...`
- [ ] added a new workflow
- [ ] modified existing workflow: `...`
- [ ] added a new table
- [ ] modified existing table: `...`

### Tests


- [ ] manually tested
- [ ] added unit tests
- [ ] added integration tests
- [ ] verified on staging environment (screenshot attached)

Author: HariGS-DB

README.md

@@ -73,8 +73,8 @@ For questions, troubleshooting or bug fixes, please see your Databricks account
 #### Install Databricks CLI on macOS
 ![macos_install_databricks](docs/macos_1_databrickslabsmac_installdatabricks.gif)
 
-#### Install Databricks CLI via curl on Windows
-![winos_install_databricks](docs/winos_1_databrickslabsmac_installdatabricks.gif)
+#### Install Databricks CLI on Windows
+![windows_install_databricks.png](docs/windows_install_databricks.png)
 
 ### Download & Install
 

docs/ucx-install.gif

@@ -38,9 +38,3 @@ def test_save_spn_permissions_local(ws, sql_backend, inventory_schema, make_rand
     az_res_perm = AzureResourcePermissions(installation, ws, AzureResources(ws, include_subscriptions=""), location)
     path = az_res_perm.save_spn_permissions()
     assert ws.workspace.get_status(path)
-
-
-def test_cli(ws):
-    from databricks.labs.ucx.cli import save_storage_and_principal
-
-    save_storage_and_principal(ws)