chore: Add `@HapiTest` readme, style guide, and spec cookbook

[tinker-michaelj]

Description:

• Closes #14046 by adding a README.md and SpecCookbook.md to the test-clients module.
• Moves SpecOperation and TargetNetworkType to more natural packages, adds some javadoc.

[github-actions[bot]]

Node: Unit Test Results

  1 545 files    1 545 suites   3h 31m 14s :stopwatch: 115 799 tests 115 740 :white_check_mark: 59 :zzz: 0 :x: 124 114 runs  124 055 :white_check_mark: 59 :zzz: 0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

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Node: HAPI Test (Restart) Results

3 tests   3 :white_check_mark:  2m 32s :stopwatch: 3 suites  0 :zzz: 3 files    0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

Node: HAPI Test (Node Death Reconnect) Results

3 tests   3 :white_check_mark:  5m 42s :stopwatch: 3 suites  0 :zzz: 3 files    0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

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Node: HAPI Test (Token) Results

 22 files   22 suites   6m 25s :stopwatch: 273 tests 273 :white_check_mark: 0 :zzz: 0 :x: 351 runs  351 :white_check_mark: 0 :zzz: 0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

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Node: HAPI Test (Crypto) Results

 24 files   24 suites   14m 4s :stopwatch: 364 tests 364 :white_check_mark: 0 :zzz: 0 :x: 371 runs  371 :white_check_mark: 0 :zzz: 0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

[github-actions[bot]]

Node: HAPI Test (Misc) Results

 51 files   51 suites   23m 7s :stopwatch: 357 tests 357 :white_check_mark: 0 :zzz: 0 :x: 375 runs  375 :white_check_mark: 0 :zzz: 0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

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Node: HAPI Test (Time Consuming) Results

19 tests   19 :white_check_mark:  22m 45s :stopwatch:  4 suites   0 :zzz:  4 files     0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

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Node: HAPI Test (Smart Contract) Results

 73 files   73 suites   22m 40s :stopwatch: 626 tests 626 :white_check_mark: 0 :zzz: 0 :x: 679 runs  679 :white_check_mark: 0 :zzz: 0 :x:

Results for commit 5b95e589.

:recycle: This comment has been updated with latest results.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 58.12%. Comparing base (9973fae) to head (9c7c438). Report is 93 commits behind head on develop.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## develop #14089 +/- ## ============================================= - Coverage 67.58% 58.12% -9.46% + Complexity 36486 22021 -14465 ============================================= Files 3732 2866 -866 Lines 149767 110020 -39747 Branches 15571 11206 -4365 ============================================= - Hits 101223 63953 -37270 + Misses 44179 42513 -1666 + Partials 4365 3554 -811 ```

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