Batch key import tool

[shrimalmadhur]

Is your feature request related to a problem? Please describe.
Need a tool to batch key import private keys and convert into encrypted keys files with password which can be used for testing

Note: This utility should be only used for testing

Describe the solution you'd like
This should create (ecdsa/bls)

• Input a private.keys.txt file which has one key per line
• A folder which has all the encrypted json files
• A private.keys.loc.txt file with one filename for each private key
• A passwords.txt file with one password for each of those keys

Describe alternatives you've considered
A clear and concise description of any alternative solutions or features you've considered.

Additional context
Add any other context or screenshots about the feature request here.