Improve argument checking in daemon

#2226 fixes parameter parsing (reported in #2224), but it does by checking parameters in the CLI client. This means that, if another client sends the daemon the same wrong parameters (`-mem 2048M`, in this case), the daemon will fail to detect the error.

While it is ok to check arguments in the client, we need to enforce checking this in the daemon. That ca be accomplished by moving instance validation _after_ the validation of the other parameters.

Start by tracing daemon parameter validation and the instance validation mentioned in the issue, then reproduce the invalid `-mem 2048M` input through a client other than the CLI. Done means the daemon itself rejects the invalid parameter consistently, with existing validation behavior preserved.

Written by the indexing model from the issue text.