Remove obsolete `dev-setup` documentation

[WadeBarnes]

The dev-setup folder contains obsolete documentation on how to setup a local development environment.

The requirement for bare metal setup has been eliminated by implementing devContainers, which provide a repeatable and sharable stable development environment.

References to any of the bare metal setup should be replaced with references to the devContainer utilization documentation.

[IshaanXCoder]

hey pls assign this task to me :)

[WadeBarnes]

@IshaanXCoder, You don't need to be assigned the task to work on it. An indication here that you are, plus a relation to an associated PR is all that is needed. In other words - Go for it!

[bougui]

Hello here is a PR for this https://github.com/hyperledger/indy-node/pull/1914