Poc: refactor to pure tests, no embedded docker/quickstart for target network

[sreuland]

What problem does your feature solve?

System tests require building a docker image with network components by version compiled into it, this embeds quickstart and results in a docker image which has bundled the compiled tests and the entire quickstart base image, this approach was originally done to avoid re-implementing the config and running of a target stellar network to test, but it has a heavy coupling on quickstart and docker, the pure tests themselves are written in go and could be compiled to a standalone binary on any native platform(arm64/amd64/win) and more portably executed from there, with no dependency on docker or quickstart.

What would you like to see?

Do a poc dev branch, to assess what can be done to remove embedded quickstart/docker from here and instead have the tests just refer to remote url for rpc. The user would be responsible for providing the RPC url to use, which could be from any deployment, or a locally running RPC service(compiled from source to local machine native platform like win,ar64amd64,etc), or it could be from a custom 'versioned stack' of the network compiled into a local quickstart image such as make build TAG=latest XDR_REF=v20.1.0 CORE_REF=v20.2.0rc3 CORE_SUPPORTS_ENABLE_SOROBAN_DIAGNOSTIC_EVENTS=true HORIZON_REF=release-horizon-v2.28.3 SOROBAN_RPC_REF=v20.3.0

What alternatives are there?