Allow a more human description of the translations guideline URL

[David Planella]

When a translation team administrator wants to link to a translations guide document in Launchpad, there is a form with a single entry which allows entering a URL.

This link is shown in four places:

1) In the list of teams in a translation group (e.g. https://translations.launchpad.net/+groups/ubuntu-translators)
2) In the translation page of a template: (e.g. https://translations.launchpad.net/ubuntu/lucid/+source/ubiquity/+pots/ubiquity-debconf/ca/+translate)
3) In the translations dashboard for a member of the translation team (e.g. https://translations.launchpad.net/~dpm)
4) In a translation team translations page (e.g. https://translations.launchpad.net/~ubuntu-l10n-ca)

These are shown differently in both places: in 1) the URL itself is shown, whereas in 2) the text "Ubuntu <language> translators guidelines" is shown (for Ubuntu).

It would be nice to unify the way the link text is presented, and have it shown in a more "human" way in both places. An idea would be to allow for a second field in the form where the URL is specified, in which the team administrators could give a more friendly (short) description of the document, to be shown in 1) and 2)

[Данило Шеган (danilo)]

All of the four places above might need unification, though it probably works fine as it is right now for 3 and 4 (I've added them for completeness)