feat(launch): automatically fetch mainnet account balances for query GenesisAccounts with mainnet

[lumtis]

The same query GenesisAccount GenesisAccountAll can be used to get the genesis account with final balances for mainent.

This simplify launching mainnet from the client perspective

The feature can be tested with Ignite CLI:

ignite network chain publish https://github.com/lubtd/orbit.git --chain-id orbit-1 --local --mainnet --total-supply 1000000orbit

ignite network chain init 2 --local
? Staking amount 9000orbit
? Commission rate 0.10
? Commission max rate 0.20
? Commission max change rate 0.01

ignite network chain join 2 --local

// need to add manually shares to the account with spnd from the coordinato
spnd tx campaign add-shares 1 spn165wt8n7n9280vqrgkjz85d4ew90fe3vt6cg8v6 50000orbit --from def -y

ignite network chain show accounts 2 --local

ignite network chain launch 2 --local

ignite network chain prepare 2 --local

The genesis contains the account balance calculated from their shares

[codecov]

Codecov Report

Merging #805 (62dd65b) into develop (53277e4) will increase coverage by 0.04%.
The diff coverage is 81.53%.

@@             Coverage Diff             @@
##           develop     #805      +/-   ##
===========================================
+ Coverage    10.50%   10.54%   +0.04%     
===========================================
  Files          332      332              
  Lines        77711    77755      +44     
===========================================
+ Hits          8164     8202      +38     
- Misses       69342    69346       +4     
- Partials       205      207       +2     

Impacted Files	Coverage Δ
x/launch/keeper/grpc_genesis_account.go	85.00% <81.53%> (+1.66%)	⬆️

[lumtis]

@Pantani @giunatale @aljo242 please review this one when you can