Optimize Fastfile

[defagos]

As a Pillarbox developer I want CI workflows to run as fast as possible.

Acceptance criteria

• The fastlane configuration has been updated to eliminate unnecessary work and to enable useless options, if available.

Tasks

• Remove unnecessary work from fastlane lane configurations (e.g. unnecessary cleanup).
• Check all fastlane actions and associated parameters. See if some improvements are available that could be enabled.

[defagos]

Not sure there remains much to be done here:

• Cleanup does not cost much and was properly implemented. We won't gain much by removing it by assuming commands will always be run on CI agents.
• Fastlane commands are properly configured otherwise. We had a look at them recently, most notably when improving test execution on CI agents.