feat: introduce a service or companion context concept #63
Description
Idea: currently we have the ability to map ports from host<-container, which means we can leverage another container from within a task using a different context, if that task is run in parallel.
Limitation: that container may/would not be shut down correctly at the end of the run as it most likely has to be started in daemon mode for it to be useful to other tasks.
Proposal: add a first class citizen property on a context to mark it as a service or companion (wording TBC) -> which essentially means we need to forcibly close it when the pipeline using it is finished.
Take care with a single task execution as well - it needs to be disposed of on SIGINT