Election with only available and authorized nodes

[apoorv-2204]

Description

We should use only authorised and available nodes for election, to have consistent shard info .

ommitted files -
node_renewal.ex
node_map live.ex

Fixes # (521)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• mix test
• distributed testing

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules