Optimize custom tax logic

[Lockwarr]

When a fee is paid in different denom than unls, then we perform a complex custom logic to determine if the fee is accepted and enough.

Optimize this custom logic to query concrete prices instead of querying all prices.

Validate the params on MsgUpdateParams by again doing a query to the contract and determine if params are okay.

Add a default value for the min_gas_prices in app.toml, hardcoded in the binary as we have for other required values such as commit_timeout.

[Lockwarr]

Try this query '{"base_price": { "currency": "OSMO"}}' -> '{"stable_price": { "currency": "OSMO"}}'

[Lockwarr]

Rename tax param contract_addr to treasury_addr

Use the base_price query for all custom fees(stables or volatile tokens) and the formula - feeAmount * (pricefeedAmountQuote/priceFeedAmount)

[Lockwarr]

Think about no queries for prices or tickers to contracts at all, just have module params for each ibc denom that we want to accept + exact minimum amount or fraction of the base denom