Rename plugin to nodejs

This plugin should be renamed to `cloudformation-cli-nodejs-plugin`. Here are the reasons:

1. All the current CloudFormation CLI plugins are the runtime used by the provider backend: Java, Python and Go. It makes sense to call them languages when the runtime and the programming language have the same name. As you see in the [AWS Lambda runtimes documentation](https://docs.aws.amazon.com/lambda/latest/dg/lambda-runtimes.html), there is no TypeScript or JavaScript runtime, but rather Node.js.
2. In the future, we could be creating the different languages in a single GitHub repository. Because you can always compile the TypeScript into JavaScript, they can share the same codebase. The following would be a list of possible language plugins to be managed from a single repository and one PyPI library:
a. TypeScript (Node.js 14.x): code scaffolding for TypeScript language but running on Node.js 14 compute.
b. TypeScript (Node.js 12.x): the same as above, but on Node.js 12.
c. JavaScript (Node.js 14.x): code scaffolding for JavaScript language but running on Node.js 14 compute.
d. JavaScript (Node.js 12.x): the same as above, but on Node.js 12.

The issue names the plugin repository and its PyPI library but no source files or tests. Start by locating references to the current plugin name across the repository and package metadata, then verify that the repository, published package, and documented references consistently use cloudformation-cli-nodejs-plugin.

Written by the indexing model from the issue text.