Duplicate localnet instructions

[ianw-da]

Path: /global-synchronizer/understand/local-testing

There seem to be three differing sets of instructions for running localnet. Could two of them be removed please?

https://docs.canton.network/sdks-tools/development-tools/localnet#localnet
https://docs.canton.network/appdev/tooling/development-tools-overview#localnet
https://docs.canton.network/global-synchronizer/understand/local-testing