Implement an upgrade of the codebase to use Slim Framework version 4, which includes the following changes:
- Updating to Slim version 4 and the corresponding AzuraCore updates.
- Making all objects PSR-7 Request/Response agnostic (and creating RequestHelper and ResponseHelper objects to interact with the PSR-7 Req/Resp objects).
- Moving to PHP-DI as a DI container and implementing its autowiring support.
Rationale: under the current system, Supervisord simply pipes its per-process logs out to stdout/stderr on Docker, meaning it has no ability to read back those logs in the case of an error, leading to cryptic error messages like "SPAWN_ERROR" instead of the actual problem. This refactors the logging to be handled by Supervisord, which also is itself capable of log rotation (removing the need for AzuraCast to rotate radio software logs).
* Separate mount points and remote relays to allow local AND remote broadcasting from one station.
* Allow a different port/mount for the outbound AutoDJ from the statistics connection.
* Initial renaming to a single global App\ namespace.
* Move CSRF/Flash under Session, move Session under Request
* Use new Request Station helper
* Unify App/Acl and App/Acl/StationAcl
* Alphabetize composer.json
Buster "Silver Eagle" Neece
Vaalyn
Buster "Silver Eagle" Neece