Change app title and move to strings.ts

## Description:
Currently, the app title is set to the default "React App". Please update it to: "First Good Issue Finder".

Additionally, add this string to strings.ts and reference it from there instead of hardcoding.

## Acceptance Criteria:

 - App title updated to "First good issue Finder"

 - String moved to strings.ts

 - Title pulled from strings.ts in the app