Content Builder should output it's execution statement at the start of its run

[SimonDarksideJ]

Intent

The legacy MGCB process pushed to the console the exact MGCB command that was used to run it, this became invaluable to running / debugging what was happening with the content build.

SO it would be immensely useful if the new system carried this capability forward.

Motivation

Currently, the new Content Builder simply outputs "Content Builder started" and does not expose the parameters or even the command that executed it.

[uygary]

Just thinking out loud: Should it utilize System.Diagnostics.Debug methods?
Or would these logs be useful in release scenarios as well?

[harry-cpp]

Neither, needs to be just a message task in the targets.