fix: Fix tinfoil issue with improper rom DL urls and support for rom folders

[KaitoKid]

Addresses the concerns in #1208

Tinfoil Parsing Issues

Root cause is the FS handler for get_roms assumes that directories with a single file inside as multi

.
├── Homebrew
│   ├── my_homebrew.nsp

which results in the following FSRom being created after the directory is scanned

{
  'multi': True, 
  'file_name': 'Homebrew', 
  'files': [{'filename': 'my_homebrew.nsp', 'size': 0, 'last_modified': 1718254179.6487029}]
}

This fix addresses two things:

1. Single files in directories being mistakenly addressed as multi
2. Changing the file path to be the actual path of the file, not the file_name. Instead, it renames the file in Tinfoil to the file_name instead.

Known Bugs

Since this takes just the first obj of each rom file, it cannot handle cases where multiple files are stored in one directory. I'll defer to the community on the best method of handling this, but a couple ideas come to mind:

1. Creating separate directories at the root level for base/patch/update
2. Standardizing file names so that titledb/tinfoil's api/something can be matched up

[KaitoKid]

Added a few more updates to address the following:

• Handling empty folders
• Addressing rom.full_path using the file_name, which is stored as the rom directory name (causes an inaccurate file redirect upon download
• Rolled back changes to the filename. I was hoping to rename it as "Rom/rom_file.nsp" within Tinfoil, but I can see that it would not pass routing rules. Leaving it without an extension causes Tinfoil to open it as a file, not as an installer

[adamantike]

rom.files[0] here now needs to be file, after the latest changes.

[adamantike]

I don't think we want to expose all files to Tinfoil. Ideally, we could only include the ones with a valid extension that Tinfoil understands (in case users maintain other kind of resources within the rom folder).

[adamantike]

@KaitoKid, please let us know if you plan to keep updating this PR.