[code-reflection] RFR: Regularize dialect factory use

[Paul Sandoz]

This PR is branched off (dependent on) #441 that groups op factory and type element factory into dialect factory.

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.

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Commit messages:
 - 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

Changes: https://git.openjdk.org/babylon/pull/442/files
  Webrev: https://webrevs.openjdk.org/?repo=babylon&pr=442&range=00
  Stats: 519 lines in 31 files changed: 189 ins; 213 del; 117 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