Remove fog provider support

[kathap]

Needs cloudfoundry/cloud_controller_ng#5288 to be in first.

Remove all fog references from job templates, specs and bpm config.

Complete fog removal follow-up for capi-release. All fog gems have been removed from cloud_controller_ng; this PR removes the remaining fog references from BOSH job templates and specs.

Changes:

• Remove fog_connection from all cloud_controller_ng.yml.erb templates and job specs (all 5 jobs: cloud_controller_ng, cloud_controller_worker, cloud_controller_clock, cc_deployment_updater,
  blobstore_benchmark)
• Remove fog_aws_storage_options and fog_gcp_storage_options from job specs and templates
• Remove cc.log_fog_requests BOSH property and FOG_DEBUG env var from bpm.yml.erb and job specs (cloud_controller_ng, cloud_controller_worker)
• Remove legacy 'AWS' provider name from storage-cli config templates; only native 's3' is now accepted
• Update all storage-cli config specs to use native provider names (s3, dav) instead of legacy fog names
• Empty local_blobstore_downloads.conf.erb — was fog-local-provider nginx config, now dead code
• Update bpm_spec to remove fog debug logging tests

• Links to any other associated PRs
  Remove fog-aws and fog-core, complete fog removal cloud_controller_ng#5288

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• I have run CF Acceptance Tests on bosh lite