[Requestor Dashboard] Make it possible to execute multiple commands on top of an existing activity

[cryptobench]

Background

During the recent cooldown sprint I started creating a Yagna artifact dashboard which would give the user the ability to visually browse what's going on with their requestor. This however resulted in the discovery that the REST API is lacking endpoints that are useful for not only this topic alone.

What

In the dashboard we would like to have the ability to run commands on a running activity. This for example could be a usecase for when you're running a service on Yagna and suddenly you want to "exec" into the container/vm and modify some system settings or view a specific logfiles content. The feature here should work in the same way that the "exec" command works in docker, where you're able to attach to a running container and run commands within a new shell.

Here's a reference image of what was envisioned

How

We need to be able to run to commands in ExeUnit at the same time.