Many of our scripts have a non-portable interpreter line for bash and
use bash-specific variables like `BASH_SOURCE`. Update the interpreter
line to be portable between various Linuxes and macOS without
complaint from posix shell users.
* Removed deprecated Spark pieces.
* Bumped HashiCorp stack versions to current as of commit date
* Bumped versions of HashiCorp stack tools
* Bumped versions, added VAULT_ADDR in GCP, removed refs to Spark in shared README
* update versions of all products and add consul-template
* update client and server user_data scripts
* modify README.md and terraform.tfvars
* fix typo in consul-template system unit file
* update AMI id