Speed improvement: User marker Avatars

[DonNicoJs]

Currently for every marker of the system an L.divicon is generated on page load and then updated / added dynamically during the interaction of the website.

Calculating all the custom icons with all the avatars is the slowest part of the page load.

Since most of the marker are anyhow 'grouped' inside a marker cluster we want to change this approach to:

• have a default icon for every marker ( same L.divicon )
• when the zoom is more than 6 /7 recalculate the visible marker icon to include the github avatar.

Hint:

to achieve this the function iconGenerator and getMarkerIcon should be investigated first inside components/MainMap.vue

[DonNicoJs]

Closing this since we implemented a delayed marker icon calculation with the use of: requestIdleCallback