Since targets didn't have a title but only a long description, every
form allowing to select targets was pretty much unusable: we either
displayed just the code or the whole description.
Now, with a concise title, it's easier to find and select the desired
target.
The titles have been copied from The Global Goals page [1].
Note we're using the `short_title` I18n key for the `title` method and
the `long_title` I18n key for the `long_title` method. We can't use
`title` as I18n key instead of `short_title` because it would affect
existing translations.
[1] https://www.globalgoals.org/
This component was rendered on different pages so there were no conflicts
with static id's.
Now in the SDG help page we are going to render them all at once, so we
convert the static identifiers to dynamic.
