Configure export settings

I like the idea of a form where a user can select several entities across entity types in order to perform one big export for all of the content that should be synced.
Default path and entities to export should also be possible.

Thinking about the default export form, there could be some more changes to make it better.

Download button should export based on the configuration, not on what is currently selected on the form (label button accordingly).
Remove the extra form to select entity types/bundles to export all content from, but merge that functionality in the Default export form.
Add checks to exclude disallowed content from the default export if the settings form has changed after setting Default export settings. For example: Taxonomy terms are allowed to be exported in the module's settings. A taxonomy term has been added to the Default export settings form. Taxonomy terms are disallowed for export in the module's settings. Download from the default export settings form should now remove any Taxonomy terms from the default export (probably same for the drush command, or add appropriate warnings/error messages)

I got some errors on install, so I put a check for empty settings in the form, and updated the install config and schema.

I tested the feature by running drush content:export --default and it works. (we should add this as instructions to the form)

Running drush content:export without --default is throwing errors from menu_ui atm.

mortona2k → changed the visibility of the branch 3363087-configure-export-settings to hidden.

I rebased the branch onto 1.4.x.

I'm just starting a new project phase and plan to use this feature to deploy our updated Page content with new layouts. Will need to Export pages as they are completed and include them in the defaults to make it easy to catch quick changes we have to make later. I also will try it out for some menu changes, and probably some other things like blocks, media, paragraphs. I think most of it should be working pretty good now, but will patch as I encounter any issues.

When you import SCS config on the target site, the IDs don't exist and the form breaks.

This should probably use UUID for the config storage, and not use autocomplete for the form.

The current form can get difficult to use when there is a lot of content. I think switching to a multivalue field instead of autocomplete tags would help. We could show the UUID from config, or the title if it exists. There could be an autocomplete field to help populate the value.