Update supported ES plans

[markdboyd]

Related to #365

Changes proposed in this pull request:

• Update supported Elasticsearch/OpenSearch plans the highest minor version for each major version, for anything above Elasticsearch 7:
  • "OpenSearch_2.11"
  • "OpenSearch_1.3"
  • "Elasticsearch_7.10"
• Refactor plan descriptions and metadata for more consistently and to remove the default engine version. Since the default engine version can and will change frequently, this makes plan metadata much more maintainable

Things to check

• For any logging statements, is there any chance that they could be logging sensitive data?
• Are log statements using a logging library with a logging level set? Setting a logging level means that log statements "below" that level will not be written to the output. For example, if the logging level is set to INFO and debugging statements are written with log.debug or similar, then they won't be written to the otput, which can prevent unintentional leaks of sensitive data.

Security considerations

None, just updating supported versions for the broker