RFR: 7903344: refactor OutputFactory to introduce various Declaration Visitor classes [v3]

[Athijegannathan Sundararajan]

> Separate visitors for each activity (duplicate removal, include symbol filtering, name mangling and output generation)

Athijegannathan Sundararajan has updated the pull request incrementally with one additional commit since the last revision:

  NameMangler does not implement TreeTranformer as suggested in code review.

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Changes:
  - all: https://git.openjdk.org/jextract/pull/81/files
  - new: https://git.openjdk.org/jextract/pull/81/files/41761542..849a8350

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jextract&pr=81&range=02
 - incr: https://webrevs.openjdk.org/?repo=jextract&pr=81&range=01-02

  Stats: 7 lines in 2 files changed: 0 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jextract/pull/81.diff
  Fetch: git fetch https://git.openjdk.org/jextract pull/81/head:pull/81

PR: https://git.openjdk.org/jextract/pull/81