C2MS12 — Refactor "Introduction to Specification" section in front matter of Document

The section titled: "Introduction to Specification" needs evaluation and at least some rework. This is largely written as a "how we got to here" section, but could use more C2MS-centric language. Also, this should be considered to be moved from the front matter to a numbered section, such as perhaps 5.1 (moving the existing 5.1 to 5.2).

If moved to a numbered section, it needs to be marked "Informative".