[DOCS] EOL Policy

[lmeyerov]

We should have an explicit EOL policy guide and, potentially, an explicit support matrix. We can then move version numbers out of other docs.

Currently available:

• Software reqs, including supporting minimums: https://github.com/graphistry/graphistry-cli/blob/master/hardware-software.md

• Support, including links to changelogs & versioning: https://www.graphistry.com/support

Graphistry EOL policy is:

• API deprecation:
  -- Avoid most deprecations by making new APIs additive vs. breaking
  -- Aim for 1+ year notification window when unavoidable
  -- Ex: We still support our 1.0 REST protocol, and are only now moving to officially deprecate it
• Fixes go into new versions (vs. LTS patching)
• Document breaking changes in the release changelog, as well as significant internal infra upgrades
• Connectors: Latest major version of a product; we will be revisiting in Q2/Q3 for supporting multi-major-versions (e.g., we support both Neo4j 3 + Neo4j 4)
• Manual support: 2yr old version for enterprise, 1yr old for cloud