Updating readme and correcting inputs

[porhkz]

Description of the proposed changes

• Readme tweaks and fixes
• Added a deploy and extra-arguments input
• Corrected checking if deploy from context-values input to deploy input. It was previously thought that the context-values input was to be used similar to how we use CDK_EXTRA_ARGS: in our current Bitbucket Pipeline for cdk deployments

Screenshots (if applicable)

• N/A

Other solutions considered (if any)

• N/A

Notes to PR author

• Testing was attempted via act, but the NocoDB repo that was being tested faced complications with the way the actual repo built using esbuild.

⚠️ Please make sure the changes adhere to the guidelines mentioned in our contribution guide.

Notes to reviewers

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