Fix install on Ruby 4 and log configure

Added

• Log where Appsignal.configure is called. When a warning is emitted about Appsignal.configure being called from an application where config/appsignal.yml or config/appsignal.rb exist, log the location from which Appsignal.configure was called alongside the location of the configuration file.

Fixed

• Fix the bundle exec appsignal install CLI command on Ruby 4 by removing the dependency on the ostruct gem, which is no longer part of the standard library.

View the Ruby gem v4.8.2 changelog for more information.