Remove hardcoded mapping and program account keys

[SEJeff]

Problem

Hardcoding mapping or program keys is not ideal. This is also hardcoded only for devnet.

pyth-client-py/pythclient/pythclient.py

Lines 17 to 19 in 8f7ade6

	V1_FIRST_MAPPING_ACCOUNT_KEY = "ArppEFcsybCLE8CRtQJLQ9tLv2peGmQoKWFuiUWm4KBP"
	V2_FIRST_MAPPING_ACCOUNT_KEY = "BmA9Z6FjioHJPpjT39QazZyhDRUdZy2ezwx4GiDdE2u2"
	V2_PROGRAM_KEY = "gSbePebfvPy7tRqimPoVecS2UsBvYv46ynrzWocc92s"

Backgrournd

There are new dns records for all of these which should be looked up at runtime via a helper:

The following dns TXT records exist as authoritative references to these keys:

devnet-mapping-v2.pyth.network
devnet-program-v2.pyth.network
mainnet-mapping-v2.pyth.network
mainnet-program-v2.pyth.network
testnet-mapping-v2.pyth.network
testnet-program-v2.pyth.network

A shell example of looking them up:

$ for network in dev main test; do
    for type in mapping program; do
        key=$(host -t TXT ${network}net-${type}-v2.pyth.network | awk -F'[="]' '/(mapping|program)=/{print $3}')
        echo "$network $type key=$key"
    done
done

dev mapping key=BmA9Z6FjioHJPpjT39QazZyhDRUdZy2ezwx4GiDdE2u2
dev program key=gSbePebfvPy7tRqimPoVecS2UsBvYv46ynrzWocc92s
main mapping key=AHtgzX45WTKfkPG53L6WYhGEXwQkN1BVknET3sVsLL8J
main program key=FsJ3A3u2vn5cTVofAjvy6y5kwABJAqYWpe4975bi2epH
test mapping key=AFmdnt9ng1uVxqCmqwQJDAYC5cKTkw8gJKSM5PnzuF6z
test program key=8tfDNiaEyrV6Q1U4DEXrEigs9DoDtkugzFbybENEbCDz

Solution

Implement some helpers to look up these keys from dns. Have that be the way to solve this in the python client.