Not clear that some configurations such as [raftstore] raftdb-path are ignored when raft engine is on (default)

File: /master/tikv-configuration-file.md

We spent sometime configuring raftdb-path in [raftstore] before realizing that this parameter was ignored due to raft engine being on by default and a different config had to be used.

The [raft-engine] enabled has a short note saying it's on by default and when it's on raftdb configs will be ignored, but it's not clear which all configs are raftdb specific. It would be clearer to add a note next to the config parameters or sections which are ignored that those won't apply unless raft-engine is off (especially since those sections will mostly be ignored with the raft engine default)

A little more confusing was that setting raftdb-path was actually getting validated in info logs (and would fail if we specified a bad dir), making it look it was used, but eventually not actually being used.

Start in tikv-configuration-file.md, especially the [raft-engine] and [raftstore] sections. Identify the raftdb-related parameters described there and make it clear which are ignored when raft engine is enabled; done means the affected configuration entries explain when they apply.