Add loading spinner to dependency vuln detail page

[timbastin]

Currently, when creating a ticket for a vulnerability, adding a comment etc. there is no loading spinner at all. We should add a spinner to all of those. Maybe we can improve the design by creating a new component called: AsyncButton which expects an onClick function which returns a promise. The isLoading logic can thus be implemented in the AsyncButton component and does not need to be reimplemented in each component which uses the button

[timbastin]

We already display a loading spinner on the details page now. Nevertheless, i think this can be improved by creating the async button component

[timbastin]

this is done!