i18n linting for .vue files under the
app/assets/javascripts/clusters/ directory

- enabled uninstallation
- give it a specific uninstall message
- ajust specs

Contemplate the scenario where a K8 managed application becomes
not_installable after being installable.

Use update term instead of update in the clusters managed app
implementation in order to make the implementation and UI
language more consistent.

This commit is the result of running `yarn eslint --fix` after enabling
the `no-implicit-coercion` ESLint rule.  This rule has been added to
our ESLint config here:

https://gitlab.com/gitlab-org/gitlab-eslint-config/merge_requests/14

They are used to indicate when knative domain name
has changed

The new component also implements several improvements in the
knative domain editor workflow:

- Display a loading spinner when saving changes in the domain name
- Display success toast message indicating changes were saved
successfully.
- Display error message in the contraty occurs

Added a changelog entry for the feature