Setup devcontainer environment

[joelrebel]

Shamelessly copied from https://github.com/infratographer/load-balancer-api/tree/main/.devcontainer
with a few changes to the vscode environment.

As of now the NATs container setup fails, because the devcontainer postCreateCommand errors out with,

[555175 ms] Start: Run in container: /bin/sh -c .devcontainer/scripts/nats_account.sh
Dumping NATS user creds file
Error: stat /home/vscode/.local/share/nats/nsc/stores: no such file or directory
Dumping NATS sys creds file
Error: stat /home/vscode/.local/share/nats/nsc/stores: no such file or directory
[559632 ms] postCreateCommand failed with exit code 1. Skipping any further user-provided commands.