Split buildpack author guide (except tutorial) into concepts and how-to

Signed-off-by: Natalie Arellano <[email protected]>

Author: Natalie Arellano

content/docs/buildpack-author-guide/caching-strategies.md renamed to content/docs/for-buildpack-authors/concepts/caching-strategies.md

@@ -1,7 +1,7 @@
 +++
-title="Layer Types"
-weight=6
-summary="Learn strategies for caching layers."
+title="Caching strategies"
+weight=1
+summary="Learn strategies for caching layers at build-time for future re-use."
 +++
 
 # Layers

content/docs/buildpack-author-guide/build-phases-overview.md renamed to content/docs/for-buildpack-authors/concepts/lifecycle-phases.md

@@ -1,9 +1,15 @@
 +++
-title="Overview of Buildpacks Phases"
-weight=15
+title="Lifecycle phases"
+weight=2
 +++
 
-We work through a full example of building a "hello world" NodeJs web application.  In the example we run `pack` on the NodeJS application to produce an application image.  We assume that we have a NodeJS buildpack, `registry.fake/buildpacks/nodejs:latest`, that is decomposed into buildpacks that help with the build.  We expand each of the buildpacks phases to explain the process.  Throughout the example we take a production-level view of their operation.  For example, our assumed NodeJS buildpack will be described to create different build, cache and launch layers in a manner similar to how a real NodeJS buildpack would operate.
+There are five phases to a buildpacks build.
+
+<!--more-->
+
+We work through a full example of building a "hello world" NodeJs web application.  
+
+In the example we run `pack` on the NodeJS application to produce an application image.  We assume that we have a NodeJS buildpack, `registry.fake/buildpacks/nodejs:latest`, that is decomposed into buildpacks that help with the build.  We expand each of the buildpacks phases to explain the process.  Throughout the example we take a production-level view of their operation.  For example, our assumed NodeJS buildpack will be described to create different build, cache and launch layers in a manner similar to how a real NodeJS buildpack would operate.
 
 ## NodeJS buildpack
 

content/docs/buildpack-author-guide/package-a-buildpack.md renamed to content/docs/for-buildpack-authors/how-to/distribute-buildpacks/package-buildpack.md

@@ -1,8 +1,11 @@
 +++
 title="Dockerfiles"
-summary="Dockerfiles can be used to extend base images for buildpacks builds."
 +++
 
+Dockerfiles can be used to extend base images for buildpacks builds.
+
+<!--more-->
+
 ## Why Dockerfiles?
 
 Buildpacks can do a lot, but there are some things buildpacks can't do. They can't install operating system packages,