Save issues and merge requests lists choice to BE

Follow up to https://gitlab.com/gitlab-org/gitlab-ce/issues/39849.

• This will save both the sort option and the direction from https://gitlab.com/gitlab-org/gitlab-ce/issues/39849 in the BE.

• If there is nothing in the BE stored, the default should be: Created date: Most recent date first (Descending).

• The choice should be unique per list type. That is, for each of the following lists, whenever the user makes a selection, it should be saved to the BE, so that whenever the user returns to the same type of list, the same selection is retained.

  • Any issue list
  • Any merge request list

• The "choice" is really made up of two selections, the type and the direction, as per https://gitlab.com/gitlab-org/gitlab-ce/issues/39849.

Suppose we have:

• A. https://gitlab.com/groups/gitlab-org/-/issues
• B. https://gitlab.com/gitlab-org/gitlab-ce/issues
• C. https://gitlab.com/groups/gitlab-com/-/issues
• D. https://gitlab.com/gitlab-com/www-gitlab-com/issues

A, B, C, D all share the same BE choice in this case because they are all issue lists.