feat: Cascading BOM with export option #619

[nlaubal]

Creation of a button to generate a bill of materials in which all levels are visible from a single element. It has an export option that allows you to select a CSV format in which you can choose the columns to export, as well as an option to ‘consolidate’ the bill of materials, which means that you export a bill of materials without duplication, but which adds the number of times the object is required.
This BOM system then allows you to anticipate potential shortages, better organise your stock and have a better overview of the creation process.

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[SchrodingersGat]

@nlaubal the existing export system already allows for exporting a complete "top to bottom" BOM for an assembly - including subassemblies.

Can you please show some screenshots of the proposed UI changes?

[nlaubal]

[matmair]

1. Please remove the translation changes, that is handled automatically
2. Please add docs for the feature you added

[SchrodingersGat]

@nlaubal the ability to "expand" the BOM is definitely needed here (we had it in the legacy UI for e.g) however I would request some changes here:

1. Remove the custom "export" functionality in the code. There is a custom (server side) export framework which already allows top-to-bottom BOM export. And it can be extended via user plugins if required.

2. Display nested BOMs as nested items

Refer to the docs here - https://icflorescu.github.io/mantine-datatable/examples/nested-tables/

It should be possible to expand each BOM row to show the subassembly BOM. Then, the user can also "collapse" that row. And for convenience we can add an "expand all subassemblies" button.

Basically, let's use the UI functionality already provided! Additionally, expanding the subassemblies as required is much more performant than fetching all BOM data. For a BOM with a very deep heirarchy this could be a very long time spent requesting bulk data.

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