This is consistent with the way we've got partials to render debates,
proposals and legislation processes on their index pages.
Note that, while adding the tests for the status icon, we're keeping one
system test because it also tests the process of voting. We're adding a
new, similar component test, where the voter is created in the database,
so all possible statuses are tested in the component.
This way we fix a bug we mentioned in commit 930bb753c which caused
links to documents to be broken when editing their title because the
title was used to generate the URL of the document.
Note we're still using Paperclip to render cached attachments because
this is the only case where we store files with just Paperclip and not
Active Storage.
With Active Storage, we render attachments just like any other resource,
using `polymorphic_path`. Paperclip included the `url` method in the
model; since the model doesn't have access to the request parameters
(like the host), this was inconvenient because it wasn't possible to
generate absolute URLs with Paperclip.
In order to simplify the code and make it similar to the way we used
Paperclip, we're adding a `variant` method accepting the name of a
variant and returning the variant.
This way we won't have to add the `inline-block` and `no-bullet` classes
to other elements and we can define the styles in one place.
Note we're using the `ul.tags` selector instead of just `.tags` to avoid
conflicts with a `div.tags` selector which is used to select tags in a
form. Renaming the selector to `.tag-list` would be better, but we
aren't doing so because it would break custom stylesheets using that
selector.
Also note we're keeping the %tags placeholder selector in `.tags`
selector in the participation.scss file. This is so styles are not
overwritten by selectors like `.debate-show ul li`, which has the same
specifity as `ul.tags li`.
