Request: index information relevant to new Penumbra homepage

[plaidfinch]

The in-progress redesigned Penumbra homepage is intended to feature a "statistics" section which shows:

• Total Value Shielded, plus a top-5 breakdown of tokens by cumulative shielded value
• 30 day DEX volume, plus a top-5 breakdown of tokens by 24 hour volume on the DEX
• Total Connected Chains, plus a top-5 breakdown of chains by current shielded value

In order to realize this as real-time data from an indexer, there are required code changes to the indexer in order to get the following information, in descending order of priority:

1. per-asset 30 day total volume (direct + swaps) on the DEX (only 24-hour volume is currently indexed)
2. per-asset current value shielded, inclusive of the UM asset and native delegation tokens (current code filters the UM asset out due to a decision made during the construction of the insights page)
3. per-asset cumulative value shielded, inclusive of the UM asset and native delegation tokens (see above)
4. list of all IBC clients on the chain (this can currently only be approximated from the data in any existing view, by counting distinct Bech32 prefixes on IBC transfers)

These modifications could be made as enhancements to the DEX and IBC components of the indexer, tracking additional events and data.