Add shuffling for header and footer template parts when zoomed out

[draganescu]

Advances #50739

What problem does this address?

#59251 introduced shuffling for patterns. We should have the same interaction available for template parts.

What is your proposed solution?

Copy the interaction we have for patterns.

[draganescu]

The problem to deal with in this issue is similar to the one in #60203 - when we shuffle a template part, what should actually happen:

1. Replace the contents of the template part (keep the same post id) in the template
2. Replace the template part (change post id) in the template

[richtabor]

when we shuffle a template part, what should actually happen:

I would expect my header to change throughout my site, wherever the corresponding template part is used.