Add more description about working in devcontainer and how connect works

[erichlf]

Is your feature request related to a problem? Please describe.
Currently it may not be clear for an end user on how to setup their environment inside the devcontainer, such as what might be necessary to have things up and running as if it were on the host machine.

Describe the solution you'd like
Add more details to the readme that spells out what a user may need to do to accomplish the replication of their environment inside the devcontainer.

Describe alternatives you've considered
There could be links pointing to how things are done in devcontainers in general, but I believe it is best to spell it out here.