Add user home page

[noyainrain]

Create a personal landing page for the user displaying the user's lists (bookmarked lists).

[noyainrain]

Depends on noyainrain/micro#68.

[noyainrain]

Draft:

class User(micro.User):
    """
    .. attribute:: lists

       class:`Lists` of the user.
    """

    class Lists(Collection):
        """
        :ref:`List`s of the user, ordered by time added, latest first.

        Lists created by the user are added automatically.
        """

        def add(self, lst, *, user):
            """
            .. http:post:: /users/(id)/lists

            ``{"list_id"}``

            Add the list with *list_id*.

            If the list is already in the collection, the associated time is updated. If there is no
            list with *list_id*, a :ref:`ValueError` is returned.

            Permission: The user oneself.
            """

        def remove(self, lst, *, user):
            """
            If *lst* is not in the collection, a :exc:`micro.error.ValueError` is raised.

            --

            .. http:delete:: /users/(user-id)/lists/(id)

            Remove the list with *id*.

            If the user is the list owner, a :ref:`ValueError` is returned.

            Permission: The user oneself.
            """

UI draft:

• /intro: Present start page, reachable via "Introduction" menu item
• /: If user has no lists yet, redirect to /intro