Generalize the maturity model pattern

[spier]

By generalizing the marity model pattern we hope to allow for other orgs to list themselves as adopters of this pattern, even if they may be using a maturity model that is different from the one proposed in this pattern.

At the same time we think that providing a maturity model as part of this pattern has its merits, as it allows readers to understand in greater depth what this goals of this pattern are.

Key changes

• rewrite Patlet into the 2 sentence form (1 problem + 1 solution)
• Generalize the Solution section. Separate the definition of the maturity model from the self-assessment of the teams.
• Formatting Forces, Context, and Resulting Context as list, to allow for easier checking

[spier]

@dicortazar I would love to get your input on the changes to this pattern, given that you were one of the original authors.