Support multiple environments: parameterize Lambda name and NR_TAGS

[jnoss]

This PR adds support for deploying multiple New Relic log ingestion lambdas in the same AWS account/region (by adding a Lambda function name suffix parameter in SAM). Before this change it was not possible to have multiple environments of the Lambda because the name of the Lambda was a static string in the SAM template; Lambda names must be unique in every AWS account/region so the Serverless Application Repository-managed lambda could only be deployed once. This PR also adds a SAM parameter for NR_TAGS to be able to configure New Relic Logs tags during the deploy of each of those Lambdas.

The use case for this has multiple aspects:

• to have separate New Relic log ingestion lambdas for different environments in the same AWS account/region in order to isolate the logging infrastructure for those environments from potential deployment/concurrency issues and allow testing of new features in a test environment
• to be able to vary the New Relic Logs tags on each of those separate lambdas, for example to identify the environment of an application sending logs to New Relic

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[mrickard]

Thank you for your contribution, @jnoss ! Would you be willing to rebase against the current master branch, and sign your first commit? (Alternatively, you could squash both into one, but we'd need that to be signed as well.)