[Frontend] PWA: Web app manifest and icons (optional)

[JayWebtech]

Overview

Optional installable dashboard experience for merchants.

Technical Requirements

• Add manifest.json and icons.
• Theme color and display standalone.
• Verify Lighthouse PWA checklist (optional).

[Psami-wondah]

@Psami-wondah has applied to work on this issue as part of the Stellar Wave Program's 3rd wave.

I would like to work on this issue because I have worked on pwa's in my personal and work projects

ℹ️ Repo Maintainers: To accept this application, review their application or assign @Psami-wondah to this issue.