feat: add ability for users to convert their password login type to oauth/github login (#8105)

* Currently toggled by experiment flag

---------

Co-authored-by: Bruno Quaresma <bruno@coder.com>

docs/api/users.md

@@ -140,6 +140,7 @@ curl -X GET http://coder-server:8080/api/v2/users/authmethods \
 
 ```json
 {
+  "convert_to_oidc_enabled": true,
   "github": {
     "enabled": true
   },
@@ -792,6 +793,43 @@ curl -X DELETE http://coder-server:8080/api/v2/users/{user}/keys/{keyid} \
 
 To perform this operation, you must be authenticated. [Learn more](authentication.md).
 
+## Get user login type
+
+### Code samples
+
+```shell
+# Example request using curl
+curl -X GET http://coder-server:8080/api/v2/users/{user}/login-type \
+  -H 'Accept: application/json' \
+  -H 'Coder-Session-Token: API_KEY'
+```
+
+`GET /users/{user}/login-type`
+
+### Parameters
+
+| Name   | In   | Type   | Required | Description          |
+| ------ | ---- | ------ | -------- | -------------------- |
+| `user` | path | string | true     | User ID, name, or me |
+
+### Example responses
+
+> 200 Response
+
+```json
+{
+  "login_type": "password"
+}
+```
+
+### Responses
+
+| Status | Meaning                                                 | Description | Schema                                                     |
+| ------ | ------------------------------------------------------- | ----------- | ---------------------------------------------------------- |
+| 200    | [OK](https://tools.ietf.org/html/rfc7231#section-6.3.1) | OK          | [codersdk.UserLoginType](schemas.md#codersdkuserlogintype) |
+
+To perform this operation, you must be authenticated. [Learn more](authentication.md).
+
 ## Get organizations by user
 
 ### Code samples