[ Enhancement ] Add alternative flow for shifting files from TF project to Tower host

[gwright99]

A recent client deployment encountered issues using the installer because their TF project needs to run on non-self-hosted Github runners which do not seem to have the requisite access privileges to configure the necessary ssh_config.

We have been asked if it is possible to modify the file deployment flow such that the TF installer can push the files to another storage medium (e.g. S3) and then have the VM itself pull and execute files from that same location.

A preliminary design being mooted is to have an extra peer flag to flag_vm_copy_files_to_instance. If this peer flag is set:

• The generated target folder will be pushed to S3.
• The TF installer will ensure the IAM Role assigned to the EC2 instance has the necessary S3 R/W rights.
• The EC2 VM init script will be modified to copy the file from S3 to itself.
• The copied files will be executed in order.

Further thought required before action to ensure there aren't any other gotchas to identify mitigate before starting work.