Allow custom paths for integrations

System Health details

This is not a bug so I dont think this is applicable.

Checklist

• I'm running the newest version of HACS https://github.com/hacs/integration/releases/latest
• I have enabled debug logging for my installation.
• I have filled out the issue template to the best of my ability.
• I have read https://hacs.xyz/docs/help/issues/
• This issue is related to the backend (integration part) of HACS.
• This issue only contains 1 issue (if you have multiple issues, open one issue for each issue).
• This is a bug and not a feature request.
• This issue is not a duplicate issue of currently open or issues pending release.

Describe the issue

Hi!

I have a repo, FredrikM97/ha-notifications, where I use GitHub Releases to create versioned ZIP files.

Since I use the ZIP release and have an action that builds the file structure. I was hoping this would allow me to avoid the nested custom_component/ha_notifications/* structure and instead have a /backend folder containing the integration files. After testing this, I noticed that it doesn't currently work and results in the following error:

Downloading FredrikM97/ha-notifications with version dev failed with (No manifest.json file found 'manifest.json')

Is it possible to support this when using ZIP releases? The ZIP release would have the correct file structure, while I assume the error occurs because manifest.json is in the wrong location in the repository itself.

The benefit of supporting this would be a less bloated GitHub repository and easier maintenance when mixing frontend and backend code.

If I linked manifest.json in root from backend/manifest.json and enable content_in_root then it seem possible to download the hacs integration as expected. Maybe we can make a shortcut of this to avoid the need for manifest at two places which would fully utilize the zip instead of the repo file structure.

Best regards, Fredrik

Reproduction steps

N/A

Debug logs

N/A

Diagnostics dump

N/A