New single balance ReadPool

[iamrz1]

A brief description of the changes in this PR:

Tasks to complete before merging PR:

• Ensure system tests are passing. If not Run them manually to check for any regressions 📋
• Do any new system tests need added to test this change? do any existing system tests need updated? If so create a PR at 0chain/system_test
• Merge your system tests PR to master AFTER merging this PR

Associated PRs (Link as appropriate):

• 0chain: New single balance ReadPool 0chain#1380
• blobber:New single balance ReadPool blobber#723
• gosdk: New single balance ReadPool gosdk#486
• system_test: New single balance ReadPool system_test#297

[service-0chain]

Manual system tests [failure] with the following config

config	value
tests skipped	FALSE
system-tests	single-balance-readpool
gosdk	NOT OVERRIDDEN
zboxcli	single-balance-readpool
zwalletcli	staging
0chain	single-balance-readpool
blobber	single-balance-readpool
authorizer	staging
0box	staging
0block	staging
0dns	staging
explorer	master
0proxy	staging
0search	staging

[service-0chain]

Manual system tests [success] with the following config

config	value
tests skipped	FALSE
system-tests	single-balance-readpool
gosdk	NOT OVERRIDDEN
zboxcli	single-balance-readpool
zwalletcli	staging
0chain	single-balance-readpool
blobber	single-balance-readpool
authorizer	staging
0box	staging
0block	staging
0dns	staging
explorer	master
0proxy	staging
0search	staging

[dabasov]

lgtm