[sugar] Feature/string freeze exception: uninstall activities from the shell

[Tomeu Vizoso]

Hi all,

has been requested that we add to the current release a new feature
after the freeze: removal of activities from the shell (currently,
only activities that have a bundle in the journal can be removed).

It's importance has been raised from deployments because children will
have big bundles installed through non-journal means and will need to
uninstall them in order to be able to install new ones due to the
limited NAND space. Examples of big bundles include wikipedia slices
and etoys images.

You can see in https://dev.laptop.org/ticket/7071 the specification
proposed by Eben. For this release, we could just add one option to
the palettes that allow the removal of that activity (patch attached
to ticket). This is pretty simple and non-invasive, but has the
drawback that makes very easy to uninstall activities inadvertently,
which can cause big problems to teachers in schools that try to keep a
base set of activities installed in the pupils' laptops.

In summary, I think that we should add an option to uninstall
activities, with a non-modal alert that asks for confirmation, thus
reducing the risk of involuntary removals. Note that this will require
three new strings to be translated (cc'ing the localization mailing
list).

Sounds good? Comments?

Thanks,

Tomeu