Added profile image to Best Streaks and Most Streaks in /community page

Wow this feature is turning out harder than expected, and a lot more work across multiple files. Poor tech estimation again! Need to get better at this.

• Optimised First Joined and Top Streaks leaderboards (using the fetchCurrentStreaks() function) to use data from asyncData() instead, thus making first paint faster
• removed fetchAccAll() from mounted() since no longer necessary
• Had to match profileImg to authors in fetchLongestStreaks() fetchMostStreaks() functions

Next: wrangling with the code for Most Goals, Most Comments and Most Posts!