Enabled plugins to detect devbox entrypoint and alter their behavior

[kadaan]

Summary

Extract getSubcommand from telemetry and use it to set the new DEVBOX_ENTRYPOINT environment variable in midcobra. Use the new env var in venvShellHook.sh to stop printing the banner when running via devbox run ...

Fixes: #1823

How was it tested?

Manually run a devbox with python package via both devbox shell and devbox run. When devbox shell is used, the banner is printed. When devbox run is used, the banner is not printed.

[kadaan]

Another example of a command that should not print the python banner:

❯ devbox services ls
You can activate the virtual environment by running 'source $VENV_DIR/bin/activate'
No services currently running. Run `devbox services up` to start them:

[kadaan]

@Lagoja @gcurtis @mikeland73 Can you offer some feedback on this? I'm game to change this if this is not how you want to approach it, but the banner messages are increasingly annoying.

[kadaan]

@Lagoja Any feedback?

[kadaan]

Any reason this was closed?

[loreto]

Hi @kadaan, I was just automatically closing PRs older than 4 months (since most of them are abandoned) without making any judgement (or reading) any particular PR.

For this one specifically, are you still hoping to check it in and do you still need feedback from John? (if yes, I can ping him to take a look and we can reopen it)