Push Own Leaderboard Entry to the Top

[GODrums]

Motivation

We want to make it as easy as possible for users to find themselves in the leaderboard.

Description

This PR adds a new entry on top of the leaderboard representing the loggedIn-user. If the user does not appear in the leaderboard yet, it provides a default replacement entry with a rank of #entries + 1.

Testing Instructions

• run application-server and webapp
• login with Github and go to the homepage
• check out different leaderboards to see if your entry is on top of the leaderboard and displays correct data

Screenshots (if applicable)

Checklist

General

• PR title is clear and descriptive
• PR description explains the purpose and changes
• Code follows project coding standards
• Self-review of the code has been done
• Changes have been tested locally
• Screenshots have been attached (if applicable)
• Documentation has been updated (if applicable)

Client (if applicable)

• UI changes look good on all screen sizes and browsers
• No console errors or warnings
• User experience and accessibility have been tested
• Added Storybook stories for new components
• Components follow design system guidelines (if applicable)

[milesha]

lgtm, thanks for the improvements 👍🏼