Merge pull request #4793 from metabase/add-starttls-smtp-authentication

frontend/src/metabase/admin/admin.js

frontend/src/metabase/admin/databases/selectors.js

frontend/src/metabase/admin/datamodel/datamodel.js

frontend/src/metabase/admin/datamodel/selectors.js

frontend/src/metabase/admin/people/selectors.js

frontend/src/metabase/admin/permissions/permissions.js

frontend/src/metabase/admin/permissions/selectors.js

.../metabase/admin/settings/components/SettingsEmailForm.jsx

...rc/metabase/admin/settings/components/SettingsSetting.jsx

frontend/src/metabase/admin/settings/selectors.js

frontend/src/metabase/admin/settings/settings.js

frontend/src/metabase/reducers-main.js

src/metabase/api/email.clj

src/metabase/email.clj