Improve combine action in data manager.

[Pebkac03]

First Check

• I used the GitHub search to find a similar requests and didn't find it.
• Checked the tasks tagged issues and verified my feature is not covered

Please provide a concise description of the problem that would be addressed by this feature.

Currently the functionality of combine in the data manager is fairly rudimentary. It allows you to delete one food and point all it's references to another food. While it works I believe there is room for improvement to make it much more efficient.

Please provide a concise description of the feature that would resolve your issue.

I propose three areas where this could be improved:

1. Make it a bulk action so you can select multiple foods and combine them all.
2. Make it combine more intelligently. You could populate empty field (like plural_name) of the kept food with one from the ones being merged into it if they contain one, you could also combine the aliases of all foods being merged.
3. Create some kind of "detect duplicates" function in the UI. Could be as simple as all ingredients with the same name.

Please consider and list out some caveats or tradeoffs made in your design decision

I do not see any caveats, it could also be implemented in steps (for example start with point 1 only) to make it easier to implement.

Additional Information

• If this is accepted I'm willing to submit a PR to provide this feature
• If this is accepted I'm willing to help maintain this feature
• I'm willing to sponsor/pay a developer to do this work