Use pre-build binaries, docker for testing

[anilcse]

Now all works great but takes a lot of time to provision and installation. To improve the speed,

• Use hard coded keys via mnemonic such that scripts can avoid querying keyring everytime for account info. We can also do by setting account, validator addresses in env.
• Use pre-build binaries (default option via BINARY_URL, UPGRADE_BINARY_URL). If they are not set, it will build binary from source
• Use docker to avoid python installation and env setup