...because loading up a Rocket while it's ignited is a bad idea.
More seriously, because 'Rocket.ignite()' will become an "execute
everything up to here" method.
Prior to this commit, it was not possible to test Rocket crates in
production mode without setting a global secret key or bypassing secret
key checking - the testing script did the latter. The consequence is
that it became impossible to test secret key related failures because
the tests passed regardless.
This commit undoes this. As a consequence, all tests are now aware of
the difference between debug and release configurations, the latter of
which validates 'secret_key' by default. New 'Client::debug()' and
'Client::debug_with()' simplify creating an instance of 'Client' with
configuration in debug mode to avoid undesired test failures.
The summary of changes in this commit are:
* Config 'secret_key' success and failure are now tested.
* 'secret_key' validation was moved to pre-launch from 'Config:from()'.
* 'Config::from()' only extracts the config.
* Added 'Config::try_from()' for non-panicking extraction.
* 'Config' now knows the profile it was extracted from.
* The 'Config' provider sets a profile of 'Config.profile'.
* 'Rocket', 'Client', 'Fairings', implement 'Debug'.
* 'fairing::Info' implements 'Copy', 'Clone'.
* 'Fairings' keeps track of, logs attach fairings.
* 'Rocket::reconfigure()' was added to allow modifying a config.
Internally, the testing script was refactored to properly test the
codebase with the new changes. In particular, it no longer sets a rustc
'cfg' to avoid secret-key checking.
Resolves#1543.
Fixes#1564.