Add "Project best practices" page

[frankharkins]

Adds a new page on best practices for ecosystem projects.

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[Eric-Arellano]

Great work!

[Eric-Arellano]

Suggested change

	Software projects benefit from using continuous integration (CI) and continuous deployment (CD):
	* [Continuous integration](https://www.atlassian.com/continuous-delivery/continuous-integration): automating the integration of changes to your code, including through the use of automated tests to ensure your changes do not break the project.
	* [Continuous deployment](https://www.ibm.com/topics/continuous-deployment): automation of your deployment/release process. Often, continuous deployment can be semi-automated, such as requiring a human to initiate the deployment.

[frankharkins]

I think it's a good idea to name-drop CI/CD so users can read about it more, but given the target audience, I think it's better as a "further reading" link at the end of the paragraph. Added in a7d02c7.

[Eric-Arellano]

Suggested change

	The simplest way to list your requirements is to put the Python version you're
	using in your `README` and include a
	[`requirements.txt`](https://pip.pypa.io/en/stable/reference/requirements-file-format/)
	file in your repository. However, this means you must manually identify your
	requirements and keep the file in sync.
	Tools such as [Poetry](https://python-poetry.org/) solve this problem by
	managing dependencies for you, which means they can keep track of everything
	you've installed. Installing a dependency through Poetry will add it to a
	"lock" file, which keeps track of the exact versions of each package you have
	installed. Users can use the lockfile to replicate your environment.
	Traditionally, many Python projects use a `requirements.txt` file to list the project's dependencies.
	You may also see `requirements-dev.txt` to list dependencies only used for contributing to
	the project, such as linters or test runners. This approach can be fine, but it has two issues:
	1) no "lockfiles", and 2) you still need to set up metadata about your project.
	Instead of the traditional requirements.txt approach, build tools such as [Poetry](https://python-poetry.org/) improve dependency management. Poetry also ensures that you properly set up metadata for your project,
	such as which Python versions you support; this metadata is necessary to
	[package your project](#package-your-project).
	Installing a dependency through Poetry will add it to a "lockfile",
	which keeps track of the exact versions of each package you have
	installed. Lockfiles are crucial for
	["supply chain security"](https://docs.github.com/en/code-security/supply-chain-security/understanding-your-software-supply-chain/about-supply-chain-security).
	Lockfiles also ensure that your project will not break overnight due to new releases of dependencies
	breaking your project; with a lockfile, your dependencies will only change when you intentionally upgrade.

[abbycross]

@Eric-Arellano Is it important to put "supply chain security" in quotes? I'd leave them off unless it's confusing otherwise.

[frankharkins]

I've incorporated this into f6977d8. I've left out the security bit as most projects are run-once programs for a specific experiment.