Filter builder blocks by average fees (all time) and average fees (last 24h/7d/30d/90d)

[ameya-deshmukh]

Currently, the top builders are filtered according to the number of blocks built.

However, a better metric to filter by could be the average fees/block value. See this tweet for more context. This could also be extended for a specific time period (last 24h/7d/30d/90d) for insights on more recent blocks.

@Anish-Agnihotri please let me know if this makes sense. Would be more than happy to figure this out and open a PR.