Add icons for switchgrid new integration

[licarth]

Proposed change

Adding icon for the new Switchgrid integration.

Type of change

• [x] Add a new logo or icon for a new core integration
• [ ] Add a missing icon or logo for an existing core integration
• [ ] Add a new logo or icon for a custom integration (custom component)
  • [ ] I've opened up a PR for my custom integration on the Home Assistant Python wheels repository
• [ ] Replace an existing icon or logo with a higher quality version
• [ ] Replace an existing icon or logo after a branding change
• [ ] Removing an icon or logo

Additional information

• This PR fixes or closes issue: fixes #
• Link to code base pull request:
• Link to documentation pull request:
• Link to integration documentation on our website:

Checklist

• [x] The added/replaced image(s) are PNG
• [x] Icon image size is 256x256px (icon.png)
• [x] hDPI icon image size is 512x512px for ([email protected])
• [ ] Logo image size has min 128px, but max 256px, on the shortest side (logo.png)
• [ ] hDPI logo image size has min 256px, but max 512px, on the shortest side ([email protected])