Convert Personal Lists to Community Lists

### Feature Request

### Problem / Opportunity

There is a way to export personal lists. However, according to Drini, there is no way to convert those exports to community lists.

Newer contributors may want to create useful lists before obtaining librarian privileges. If they create some lists that are useful, it would be great for them to share them with the whole community who can collaborative improve upon those lists.

Additionally, if a group of people are dividing work to collaborate on separate parts of a carousel or collection, it would be great to add those parts easily to a community collection later.

Also, while working on a community list, one might want to list the books whose metadata needs cleanup, before creating an intentionally community-facing list. But if you do that now, you would then be creating a lot of duplicate work porting the records over once they are ready to be in the community list.

Patrons can port a personal list to a community list (possibly contingent on librarian access).

### Proposal

Allow the export files from a personal list to be easily imported to create a community list.

Why would these exports not then be able to be imported.

### Breakdown

### Related files

Refer to [this map of common Endpoints](https://github.com/internetarchive/openlibrary/wiki/Endpoints):
*

### Requirements Checklist
Checklist of requirements that need to be satisfied in order for this issue to be closed:
* [ ]

### Stakeholders

### Instructions for Contributors

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Read the linked map of common Endpoints first, then locate the existing personal-list export and community-list creation or import entry points. Clarify the intended access rules and conversion flow before implementation. Done means a personal list export can be used to create a community list without duplicate manual work.

Written by the indexing model from the issue text.