Allow Large Users to Purchase Premium Services and Additional Validators on the Mobile App for a Per-Validator Monthly Fee

[GDGitReporter]

The beaconcha.in dashboard is hard-capped at 100 validators, with no option to increase that.

The mobile app allows users to subscribe for $24.49 per month to add up to 280 validators on their mobile dashboard.

The web dashboard should offer a similar feature. But there is no particular reason either the web dashboard or mobile app needs to be capped at 280 validators.

Suggestion: Allow users to subscribe for $0.10 per month per validator to have access to the premium services, including more than 100 validators on both the mobile and web versions.

If a user has 150 validators, they would pay $15 per month, and could have 150 validators on their web and mobile app.

If a user has 800 validators, they would pay $80 per month.

If a user has just 10 validators, they could pay $1 per month to get access to the other premium features, even though they aren't hitting the 100 validator cap.

Right now the premium subscription only appeals to a very small subset of stakers -- those with between about 125-280 validators.

Less than 100 validators -- free version is fine
100-125 validators -- free version works for the first 100, and the rest are okay without; it's not worth paying $25/month for the incremental data
125-280 validators -- target customers!
281 and up -- These whales can't access all their validators on the dashboard anyway, so why subscribe?

You might also find that by adding a per-validator subscription, users with just 1 or 2 validators might subscribe just to get access to additional features like custom alerts and no ads. You could have a minimum charge of $1 per month, or $10 per year to keep the accounting easier. Or license the validators in blocks of 10 for $1 per month.

This is the same feature request as
gobitfly/eth2-beaconchain-explorer#1064
but is put here since it suggests improvements to both web and mobile versions.

[manuelsc]

As mentioned in the other issue, web already supports premium features too. Will keep this issue open for the more than 280 validator request.