Fix aes_store test variables naming
Fix testing gpg keyring creation/destruction
Document testing environment helpers
Refactor test keyring helpers
Refactor system test helpers loading
Move gpg related test helpers in a dedicated file
Move env related test helpers in a dedicated file
Fix tests potential double keychain entry
Move store related test helpers in a dedicated file
Simplify trousseau test binary detection
Change test setting to run locally to tests file in a sandbox