docs: add project layout standards

This document describes our official layout standards. It serves as a
guide for contributors to help them in organizing code and placing
packages into the correct locations.

Signed-off-by: Andrew Rynhard <andrew@andrewrynhard.com>

docs/community/project-layout.md

@@ -0,0 +1,61 @@
+# Project Layout Standards
+
+In this document we will cover our official layout standards.
+You will find that the project is a monolithic repository that contains
+everything required to build and run Talos.
+
+```bash
+$ tree .
+.
+├── api
+├── cmd
+├── docs
+├── hack
+├── internal
+│   ├── app
+│   │   ├── app1
+│   │   │   ├── internal
+│   │   │   ├── pkg
+│   │   │   └── proto
+│   │   └── app2
+│   │       ├── internal
+│   │       ├── pkg
+│   │       └── proto
+│   └── pkg
+└── pkg
+```
+
+## Internal Applications
+
+Talos is comprised of applications designed to handle the various domains of
+an operating system.
+The following requirements must be adhered to by an `app`:
+
+- anything ran as a service, that is maintained by us, should live under `internal/app`
+- each `app` is allowed at most 1 level of an `internal` package
+
+## Internal Packages
+
+There are a number of packages we will need to maintain that are strongly
+coupled with Talos business logic.
+These package should be housed within the `internal/pkg` directory.
+The criteria for deciding if a package should be housed here are as follows:
+
+- code that is a high level abstraction specific to the internals of Talos
+- code that should not be exposed publicly
+
+## Public Packages
+
+In building higher level abstractions, we should strive to create generic,
+general use packages that can be used independent of Talos.
+The following rules apply to public packages:
+
+- a `pkg` should _never_ contain `internal` code
+
+### Graduation Criteria
+
+In deciding if a package should be moved to an external repository, the
+following should be taken into consideration:
+
+- are there requests for exposing the package?
+- are there people willing to maintain the package?