Integrate @formatjs/intl as a replacement for t()

[Etheryte]

What does this PR change?

Our current translation wrapper t() is a simple hand-rolled solution that works for basic translation, but notably does not support translations with DOM nodes mixed in etc. This PR integrates @formatjs/intl as a near drop-in replacement to add support for the missing functionality and simplify many of our existing translations.

@formatjs/intl, the library internally used by react-intl, was picked over a vanilla react-intl setup to accommodate for our SPA architecture around senna which makes it difficult to use global wrappers such as intl providers. If we ever drop senna, we can easily swap out @formatjs/intl for react-intl.

Notable changes:

No more numeric replacements, all replacements must now be named.

Before:

t("Items {0} - {1} of {2}", from, to, total);

After:

t("Items {from} - {to} of {total}", { from, to, total });

Support for mixing DOM and React components into translations has been added, meaning no more chopped up translations.

Before:

<p>
  {t("Successfully bootstrapped host! Your system should appear in ")}
  <a className="js-spa" href="/rhn/manager/systems/list/all">
    {t("systems")}
  </a>
  {t(" shortly. If it is a transactional system, please reboot it to finish registration.")}
</p>

After:

<p>
  {t(
    "Successfully bootstrapped host! Your system should appear in <link>systems</link> shortly. If it is a transactional system, please reboot it to finish registration.",
    {
      link: (str) => (
        <a className="js-spa" href="/rhn/manager/systems/list/all">
          {str}
        </a>
      ),
    }
  )}
</p>

GUI diff

No difference.

• DONE

Documentation

• No documentation needed: only internal and user invisible changes

• DONE

Test coverage

• Unit tests were added

• DONE

Links

Fixes https://github.com/SUSE/spacewalk/issues/20449
Tracks https://github.com/SUSE/spacewalk/issues/21208

• DONE

Changelogs

Make sure the changelogs entries you are adding are compliant with https://github.com/uyuni-project/uyuni/wiki/Contributing#changelogs and https://github.com/uyuni-project/uyuni/wiki/Contributing#uyuni-projectuyuni-repository

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Re-run a test

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• Re-run test "changelog_test"
• Re-run test "backend_unittests_pgsql"
• Re-run test "java_pgsql_tests"
• Re-run test "schema_migration_test_pgsql"
• Re-run test "susemanager_unittests"
• Re-run test "javascript_lint"
• Re-run test "spacecmd_unittests"

[parlt91]

This is a really valuable addition. TYVM
See two really small remarks below