The start up sequence of processes that are based on the .fdroid.* metadata
is a bit different, so this ensures that the environment variables get
properly initialized in all cases.
This also creates a single function where the environment is set. Before
it was being set in multiple places across multiple files.
This simplifies usage, goes from
app['Foo']
to
app.Foo
Also makes static analyzers able to detect invalid attributes as the set
is now limited in the class definition.
As a bonus, setting of the default field values is now done in the
constructor, not separately and manually.
Don't log and exit in an inner metadata function. Handle it at a higher
level and do a proper exception. This also avoids unnecessary passing of
apps all around.
