21583: Configure Passenger with passenger_preload_bundler

21583: Configure Passenger with passenger_preload_bundler

This helps avoid situations where Passenger loads gems that create
a conflict with our bundle. We're currently seeing this with the base64
gem, where Passenger on Ruby 3.[0-3] can load the version shipped with
that Ruby before our RailsAPI bundle gets loaded. This causes an error:

  [ E 2024-03-12 15:12:44.8347 907382/Tf age/Cor/App/Implementation.cpp:221 ]:
  Could not spawn process for application /var/www/arvados-api/current:
  The application encountered the following error: You have already
  activated base64 0.1.1, but your Gemfile requires base64 0.2.0. Since
  base64 is a default gem, you can either remove your dependency on it or
  try updating to a newer version of bundler that supports base64 as a
  default gem. (Gem::LoadError)

Arvados-DCO-1.1-Signed-off-by: Brett Smith <brett.smith@curii.com>