[Test Framework] Add transaction execution support

[SupunS]

Work towards #331

Description

Add support for running transactions against the blockchain instance.

Also allows creating accounts, which would need to sign and authorize transactions.

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• [ ] Targeted PR against master branch
• [x] Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• [x] Code follows the standards mentioned here
• [x] Updated relevant documentation
• [x] Re-reviewed Files changed in the Github PR explorer
• [x] Added appropriate labels