More on issue #7318666: hide developer options from user build

The Dev Tools app now tries to add a link to Development Settings
at the top of its list.

Also add a new "Development Settings" app that directly takes you
to the development settings activity, as a stand-alone app that
could be distributed as a regular third party app.

Change-Id: I8fe2b6a32cf4e37d69f4ce7b8d646a147b492d99
9 files changed