change naming from Binance Smart Chain (BSC) to BNB Chain

[varnarmat]

What does this PR do?

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Motivation

License

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More

• Yes, I have tested the PR using my local account setup (Provide any test evidence report under Additional Notes)
• Mandatory for new node blueprints. Yes, I have added usage example to the README.md file in my blueprint folder
• Mandatory for new node blueprints. Yes, I have implemented automated tests for all stacks in my blueprint and they pass
• Mandatory for new node blueprints. Yes, I have added a reference to my README.md file to website/docs section for this feature
• Yes, I have set up and ran all pre-merge quality control tools on my local machine and they don't show warnings.

For Moderators

• The tests for all current blueprints successfully complete before merge?
• Mandatory for new node blueprints. All pre-merge quality control tools and cdk-nag tools don't show warnings?
• Mandatory for new node blueprints. The deployment test works on blank AWS account according to instructions in the README.md before merge?
• Mandatory for new node blueprints. The website builds without errors?

Additional Notes