Remove deprecated code for 9.0

[Rowlando13]

[Rowlando13]

Should do this for next feature release

[kdeldycke]

Superseeded by #3481

[davidism]

Deprecated code, such as BaseCommand, the parser module, etc, different than remaining compat stuff in that issue.

[kdeldycke]

Deprecated code, such as BaseCommand, the parser module, etc, different than remaining compat stuff in that issue.

Make sense, these are still lingering in the code base. Targeting 9.0 then.

[Rowlando13]

This is vague and redundant. Going to close see #3154 as 9.0 gets closer.

[kdeldycke]

This is vague and redundant. Going to close see #3154 as 9.0 gets closer.

I guess you created this issue as a reminder of the first task to do as soon as we prepare 9.0.0, which is removing all deprecated code right? So why not keep this open an keep an inventory of stuff to delete in the body of that issue?