Rework workflow documentation

The workflow documentation is a bit of a mess. Rework the documentation:

• Split the details out of the platform guide, making it a better high level overview of Apertis targeted more at selling the platform.
• Create an architectural document covering the basics of the Apertis workflow and how the tools used by Apertis fit together. Use pictures to help explain.
• Detailed information about workflows shifted to guides
  • Packaging guide starting to be restructured to better cover workflows by adding sections.
  • Separating out description of component repository layout into its own guide.
  • Shift image creation details to Image building guide.

While I've noticed:

• Packages have been moved from repository based sub-directories under pkg/ to pkg/ its self. Update the URLs used on the website to reflect this.

Signed-off-by: Martyn Welch martyn.welch@collabora.com

content/architecture/workflow-guide.md

@@ -144,18 +144,18 @@ images capable of being later updated via OSTree.
 
 ![Multi-stage OSTree image generation](/images/workflow_multi-stage-ostree-image-generation.svg)
 
-This split allows the creation of just one SoC, platform or even board specific
+This split allows the creation of just one SoC-, platform- or even board-specific
 recipe which can be combined with a selection of more generic recipes to enable
 either a single generic recipe to be used to fulfill the same use case across
 multiple platforms or different generic recipes to be combined with the same
 platform-specific recipe to use the same platform for different use cases.
 
-For instance the `target` and `minimal` recipes for `arm64` could be combined
+For instance, the `target` and `minimal` recipes for `arm64` could be combined
 with the U-Boot and Raspberry Pi recipes to generate four possible combinations
 of flashable images, targeting either the Renesas R-Car or Raspberry Pi
 platforms.
 
-A GitLab CI/CD pipeline will periodically schedule a batch of tests against the
+A GitLab CI/CD pipeline periodically schedules a batch of tests against the
 latest images on the
 [LAVA instance hosted by Collabora](https://lava.collabora.co.uk). LAVA takes
 care of deploying the freshly generated images on actual target devices running