Explore how to reduce fees for IBC transactions

[rootulp]

Context

#2807

Problem

There currently isn't a way for IBC relayers to forward the fees associated with relaying transactions onto users. This means that IBC relayers operate in an unsustainable way in that they have to pay these fees out of pocket. Since Celestia has a default min gas price of 0.1, the fees IBC relayers pay are higher than other Cosmos chains.

Proposal

In the short term, consider charging IBC transactions less than other transactions to make it less unsustainable to run an IBC relayer for Celestia. Note: there doesn't seem to be a parameter we can tune to easily modify the fees associated with IBC transfers so investigation is needed on how best to do this.

In the long term adopt ICS29 to incentivize relayers.

cc: @qubelabsio

[rootulp]

Partially mitigated by #2843

[rootulp]

Closing for now b/c largely mitigated by #2843