Ability to export media (attachments) on their own

[PhilipLakin]

Currently the only option for exporting media (attachments) is by exporting all. Sometimes you might not want that, in the same way that sometimes you only want a certain category of blog post, or only pages changed since March.

I have created a patch which addresses this in a similar manner to the exporting of other custom post types.

[PhilipLakin]

patch file to enable media export

[wonderboymusic]

In 34326:

Export: allow Media to exported separately from other types.

Props PhilipLakin.
Fixes #32230.