Control command should be able to optionally block

[Geod24]

Currently, control command never block, as blocking is achieved by the client:

localrest/source/geod24/LocalRest.d

Line 1235 in 1924790

return this.conn.waitResponse(command.id, this.timeout);

This can create undesirable situations, for example when things need to be restarted in a certain order to avoid crashes.

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Actually a synchronous start could also make sense 🤔

EDIT: Less of a worry because we got a channel we can wait on.