Datasource: Remove support for unencrypted passwords (#49987)

* Datasource: Remove support for unencrypted passwords

* regenerate swagger

* [WIP] Remove references to datasource password and basic auth password fields (#50015)

* try delete moar tings

* delete provisioning stuff

* remove from yaml

* update snapshots

* remove lingering snapshot fields

* fix ds http settings

* Re-generate swagger and fix swagger-api-spec make target

Co-authored-by: Will Browne <will.browne@grafana.com>
Co-authored-by: Will Browne <wbrowne@users.noreply.github.com>

docs/sources/datasources/alertmanager.md

@@ -37,5 +37,6 @@ datasources:
     # optionally
     basicAuth: true
     basicAuthUser: my_user
-    basicAuthPassword: test_password
+    secureJsonData:
+      basicAuthPassword: test_password
 ```

docs/sources/datasources/loki.md

@@ -255,7 +255,6 @@ datasources:
     url: http://localhost:3100
     basicAuth: true
     basicAuthUser: my_user
-    basicAuthPassword: test_password
     jsonData:
       maxLines: 1000
       derivedFields:
@@ -272,6 +271,8 @@ datasources:
         - matcherRegex: "traceID=(\\w+)"
           name: TraceID
           url: 'http://localhost:16686/trace/$${__value.raw}'
+    secureJsonData:
+      basicAuthPassword: test_password
 ```
 
 Here's an example of a Jaeger data source corresponding to the above example. Note that the Jaeger `uid` value does match the Loki `datasourceUid` value.