PMC proposals/Overhaul

I propose to overhaul the Bylaws in this manner:

• https://github.com/apertium/organisation/pull/13 - discussion is happening here.
•  https://github.com/apertium/organisation/blob/overhaul/Bylaws.md
•  https://github.com/apertium/organisation/blob/overhaul/CLA-optional.md

Goals of the changes

• Prepare for creating a legal entity for Apertium. But that will come later; this overhaul is needed regardless.
• Rename Developer to Contributor.
• Rename Committer to Voting Member. Not merely Member, as that would be confused for member of the Github organisation. Anyone can be a Github member, but it has to be a conscious choice to want to be a voting member.
• Separate the definition of Contributor with commit access and Voting Member. Being a voter should not be tied to having commit rights. This tie made sense with a monorepo, but it really doesn't make sense with split decentralized repos.
• Empower Contributors to do what they're effectively doing anyway (make releases, grant access), while still keeping PMC oversight for big changes.
• Recommend a Contributor License Agreement, but at least require that licenses must be clear. I'm tired of resolving licensing issues.
• Raise inactivity limit to 2 years.
• Formally ensure we reduce the bus factor and security risks.
• Change PMC voting system to STV.
• Formalize tie-breaker mechanics, since it just became relevant.
• Add an escape hatch that lets a PMC minority force a full Assembly vote.
• Add voting member removal mechanism, in case of misbehavior.
• Reduce some PMC decisions to only require a single member's approval.
• Codify how we practically operate, rather than how we would operate in an ideal world. We're currently breaking the bylaws in several ways, so the intent is to adjust most of those points so that we are not violating them.
• Ensure that voting rights are not tied to code contributions. You can be an active contributor in many ways, including end-user support, writing papers, community outreach, administrative duties, etc.

Interpretation of changes

• The idea is that for many daily administrative tasks, a single PMC member is empowered to do them. These are still PMC decisions, and as such must still be logged and presented to the Assembly regularly.