Review version variance across clients

## Expected Behavior
Currently the crawler is pulling a count for the `version variaance across clients` seems to be scraping well. However, there are some improvements that can be made. Ideally, we should be able to categorize as many nodes into their proper {client}{version} categories.

## Current Behavior
For example, in Prysm there is a group of `prysm unknown` and `prysm others` which is generally meaningless and we should figure out why.

Nimbus is also not being properly detected as they are all grouped under `unknown`. We can liaise with them to figure out how to best detect them.

Lodestar's UserAgent needs to be updated. See https://github.com/ChainSafe/eth2-crawler/issues/200 and https://github.com/ChainSafe/lodestar/issues/4465

## Possible Solution
Let's implement the UserAgent update for detecting Lodestar and figure out how we can more accurately represent the other clients to the most accurate numbers as possible.