Improve import UX

[gatzjames]

changelog(Improvements): Improved the way imports are handled to avoid issues similar to #4274 where sometimes users would import a file, see a success message but data would not be properly imported

Highlights:

• Revamped UX for importing. Display what is about to be imported and where and allow to edit the import location.
• Moved import logic in routes
• Importing is done in 2 phases:
  • Scan: parse resources from the input and map them to Insomnia models
  • Import: the parsed resources to the location (project/workspace) provided by the user

TODO:

• Clean up UI styles
• [ ] Add supported import icons to the Settings/Data tab
• Simplify importResources logic in common/import
• Error handling

Future work:

• Since we don't rely on the order of imports anymore because of the scan phase we can turn the import process into a stream to handle large resources. This would also enable cancelation in the middle of an import and allow us to rollback any updates to the db.
• Handle multi-workspace imports and importing from commands

Closes INS-2439
(Potentially) Closes #4274, #4246, #2771, #4283, #5558