[code-reflection] RFR: Regularize dialect factory use [v2]

[Paul Sandoz]

> This PR is branched off (dependent on) #441 that groups op factory and type element factory into dialect factory.
> See diff from here https://github.com/openjdk/babylon/pull/442/commits/9099bb6ba4359d73e57b77db5a8e7e75bd427116 (since we have yet to set up the Babylon repo for dependent pull requests).
> 
> Regularize the declaration of factories and the use of dialect factories. Sets the stage for further refactoring in one or more subsequent PRs that may consolidate within `DialectFactory` and/or under separate package.

Paul Sandoz has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains eight commits:

 - Merge remote-tracking branch 'upstream/code-reflection' into dialect-factory-use
 - Regularize use of factories.
 - Simplify
 - Access control and docs
 - Clean ups and docs.
 - Clean up imports
 - Remove dialect factory parameter.
 - Group op and type elem factory into dialect record

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Changes: https://git.openjdk.org/babylon/pull/442/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=442&range=01
  Stats: 323 lines in 24 files changed: 121 ins; 134 del; 68 mod
  Patch: https://git.openjdk.org/babylon/pull/442.diff
  Fetch: git fetch https://git.openjdk.org/babylon.git pull/442/head:pull/442

PR: https://git.openjdk.org/babylon/pull/442