Use 0x address (Spike)

[ethanfrey]

Closes #128

This is a WIP to change all usage of addresses to 0x format (currently canonical format is checksumed, do we want to store as lowercase hex instead?)

The purpose is to determine

• How hard to change our code to work like this (also ensure it works/stores with contracts)
• How hard to change internal tools (using cosmjs, cosmrs, cw-orch, cw-multi-test) to use this format?
• How hard to change external tools (eg keplr, webapps) to use this format

Even if we just find (and don' solve) the external blocks, this will help us contact those tams for support

[ethanfrey]

Okay, around cosmjs stuff... this was mentioned here: cosmos/cosmjs#1351

And there seems to be a gist on how to sign with cosmjs/keplr with different address type: https://gist.github.com/phips28/bf157476a3c798b09c3edffa8a149996

I did build the latest state with ./scripts/build_docker.sh and ./localnode/run.sh. And then ran the tests via cd js && npm run test. I get the following expected result:

9) Cw20 Test Cases happyPath works with gas price simulation
  - Error: Query failed with (1): Address: invalid string length

This is due to bech32 address string not 0x string. (I think it is first checking for even-length string to see if it is hex). Would be a good place to start digging into. That or the failing cosmrs test