Normalize/Normalise and the Remove DC offset effect

**DC offset**
I note that in AU4 we now have a useful new command in the **Volume and compression** menu for **Remove DC offset**.

In AU3 and earlier DC offset could only be removed by using the **Normalize** effect. AU4 for some reason still retains a facility for DC offset removal in the **Normalise** effect.

a) surely this is now redundant (and unnecessary duplication) in the in the **Normalise** effect.

b) DC offset removal is something that should be done very early in the editing process (immediately after recording, if necessary) and in contrast normalization should be one of the very last things - another good reason for removing the DC offset removal from the **Normalise** effect.

Locate the Normalize/Normalise effect implementation and the Volume and compression > Remove DC offset command, then compare how each exposes DC-offset removal. Done means the redundant DC-offset option is removed from Normalize while the standalone command remains available; the issue names no specific files or tests.

Written by the indexing model from the issue text.