smhp: quality-of-live improvements

[verdimrc]

Issue #, if available: N/A

Description of changes: Upstream from the playground repo. These are off by default. Edit the config.py to switch on.

• ssh to compute nodes from intra-cluster no longer ask for host key
• install mountpoint-for-s3
• install git-remote-codecommit to connect to Amazon CodeCommit
• fix Alt (Option) bash shortcuts when connecting from MBP
• generate keypair for ubuntu, if home dir doesn't already have one. Use-case: when re-using FSx Lustre filesystem
• generate how-to install miniconda3
• install additional CLI tools (see install-pkgs.sh)

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