Drag'n'drop added/existing file entries, add empty folder

[fiskus]

• Moved FilesState to PackageDialog/FilesState.ts, so I can easily write tests
  • also, moved getNormalizedPath because it was used only for FilesState

Add empty folder:

• Added FilesState.AddFolder
• Added "Add new folder" button
• For creating empty folder, I virtually add ".quiltkeep" file. Then I don't insert this file in UI, and ignore it when submit

Drag'n'Drop:

• Added FilesState.Move({ source: string, dest: string }) for added and existing files and directories (so, 4 types of source, dest is always an added directory)
• To have more control, I added draggable handler for file/dir icons only
• Added DndProveder for managing state: what file do we drag, above what directory, and handle drop.

simplescreenrecorder-2024-06-17_16.23.48.webm

• [x] Changelog entry (skip if change is not significant to end users, e.g. docs only)

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 46.03175% with 136 lines in your changes missing coverage. Please review.

Project coverage is 37.33%. Comparing base (3e55c58) to head (705bf28).

Files	Patch %	Lines
...app/containers/Bucket/PackageDialog/FilesInput.tsx	0.00%	120 Missing :warning:
catalog/app/components/Dialog/Prompt.tsx	0.00%	12 Missing :warning:
.../app/containers/Bucket/PackageDialog/FilesState.ts	98.30%	2 Missing :warning:
...iners/Bucket/PackageDialog/PackageCreationForm.tsx	0.00%	2 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #3999 +/- ## ========================================== + Coverage 37.19% 37.33% +0.14% ========================================== Files 757 758 +1 Lines 33135 33321 +186 Branches 4854 4903 +49 ========================================== + Hits 12323 12442 +119 - Misses 19652 20235 +583 + Partials 1160 644 -516 ``` | [Flag](https://app.codecov.io/gh/quiltdata/quilt/pull/3999/flags?src=pr&el=flags&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=quiltdata) | Coverage Δ | | |---|---|---| | [api-python](https://app.codecov.io/gh/quiltdata/quilt/pull/3999/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=quiltdata) | `90.75% <ø> (ø)` | | | [catalog](https://app.codecov.io/gh/quiltdata/quilt/pull/3999/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=quiltdata) | `11.01% <46.03%> (+0.44%)` | :arrow_up: | | [lambda](https://app.codecov.io/gh/quiltdata/quilt/pull/3999/flags?src=pr&el=flag&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=quiltdata) | `88.18% <ø> (ø)` | | Flags with carried forward coverage won't be shown. [Click here](https://docs.codecov.io/docs/carryforward-flags?utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=quiltdata#carryforward-flags-in-the-pull-request-comment) to find out more.

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[fiskus]

• Left only that "Add folder" icon on the top. And swap with "Undo changes"
• Enabled drag'n'drop only for "added", "modified" or existing "unchanged" files and directories
• Squashed commits

[nl0]

Squashed commits

i don't think it's a good idea tbh, because it makes incremental review hard. commits are automatically squashed when the PR is merged anyways.

[fiskus]

commits are automatically squashed when the PR is merged anyways.

I didn't know. Last time I checked, they didn't

[nl0]

commits are automatically squashed when the PR is merged anyways.

I didn't know. Last time I checked, they didn't

check out the network graph under the "insights" tab

[fiskus]

I mean: yes, commits are squashed, but messages were just concatenated earlier. I didn't notice when it was changed

[nl0]

I mean: yes, commits are squashed, but messages were just concatenated earlier. I didn't notice when it was changed

oh i see what you mean. we tweaked that setting some time ago, yep