ESQL: Timezone query setting and added to the query config

[ivancea]

Draft

This PR should cover until the query setting is accessible from the Configuration. Merging it before that could mean merging APIs that actually don't fit well in some way.

PR roadmap

• Convert the query settings into something similar to the cluster setting objects, having an automatic parser to convert them to values and so on (Example)
  • Reusing those classes look not too straightforward, as we use ESQL Expressions, not strings
  • Add a parser and a default value. Because they're generic, I had to transform the enum into static fields
  • Organize tests to easily add more settings there
• Add the values to the Configuration object, with a simple API like configuration.getSetting(QuerySettings.TIME_ZONE)
  • For that, the QuerySettings class must be visible from wherever it's used, or the constants should be localized in some common place. Check this!
  • TransportVersion to share them

Depending on the size of the final PR, I may move the time_zone related things to another one.

[github-actions]

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