Change Composition Analysis Complete to realistic

Why is this change being made?

Moving the complete maturity dates to be more realistic for composition analysis. Due to the priorities changes as discussed here: gitlab-org/secure/general#65 (closed) we are changing the definition of complete to be more comprehensive for dependency scanning, and deprioritizing the other two categories.

Does this MR meet the acceptance criteria?

Conformity

• Added description to this MR explaining the reasons for the proposed change, per say-why-not-just-what