Update sample properties file

Update the default locale config to also specify the encoding.
Merge pull request #1291 from elyezer/fix-sample-properties

Update sample properties file
Make `ContentView` readable, trim down smoke test

Make `ContentView` inherit from `EntityReadMixin`. use this mixin to trim down
module `tests.foreman.smoke.test_api_smoke`: replace many usages of `client.get`
with `ContentView.read_json`.