Restructure (some) of the markdown to focus around specific configuration issues

[edwbuck]

After the markdown has been transitioned to manually maintained markdown, the manually maintained markdown should be transitioned to highlight specific configuration topics. Proposals for the initial set of configuration topics include:

1. The settings that need to be changed to pull from a local image repository
2. The settings that need to be changed to alter the image name / tags for repackaged SPIRE Servers / SPIRE Agents
3. The settings that need to be altered to specify a specific volume persistence type.
4. The settings that need to be altered to enable / disable / configure Tornjak
5. The settings that need to be altered to enable / disable / configure the Spire Controller Manager
6. The settings that need to be altered to enable / disable / configure a root or child tiered cluster

The goal is not to deliver all of these items in one PR. The goal is to deliver at least one of these items in a PR so we can have an output target for evaluating future generation tools. Unattempted topics should be split into new "future" Issues.