update nft placeholder icons

[kraftjs]

Summary

Please summarize your changes, describing what they are and why they were made.

Update placeholder icons to newly provided ones by design.

Changelog

- Create svg placeholder file for each parent MIME type and an unknown placeholder
- Add created svgs to enums and rest of file structure
- Adjust NftPlaceholder icon shown depending on NftMediaContainer size
- Adjust detailsView and galleryView styling to suit nftPlaceholderIcons

Relevant Issues

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Closes #5172

Testing

Platforms

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• Desktop
  • MacOS
  • Linux
  • Windows
• Mobile
  • iOS
  • Android

Instructions

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...

Checklist

Please tick all of the following boxes that are relevant to your changes.

• I have followed the contribution guidelines for this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have added or modified tests that prove my changes work as intended
• I have verified that new and existing unit tests pass locally with my changes
• I have verified that my latest changes pass CI workflows for testing and linting
• I have made corresponding changes to the documentation