refactor: Reaction event handler

[Leonelmarianog]

Summary

Refactors reaction event handler because the code was chaotic and hard to follow. This change should make the code cleaner and easier to understand.

Details

• Renames reaction event handler to "handleRobotFaceReaction".
• Moves reaction event handlers to their own folder event/reaction.
• Updates and organizes tests because previous tests were hard to follow.

[github-actions]

LCOV of commit 6a080d5 during CI workflow #24

Summary coverage rate:
  lines......: 96.3% (602 of 625 lines)
  functions..: 98.1% (102 of 104 functions)
  branches...: 85.1% (149 of 175 branches)

Files changed coverage rate:
                                                                           |Lines       |Functions  |Branches    
  Filename                                                                 |Rate     Num|Rate    Num|Rate     Num
  ===============================================================================================================
  src/config/env.config.ts                                                 | 100%      4|    -     0|    -      0
  src/events/index.ts                                                      | 100%      7| 100%     1|    -      0
  src/events/reaction/__test__/fixture/robotFaceReactionEvent.ts           | 100%      2|    -     0|    -      0
  src/events/reaction/__test__/fixture/webclient.ts                        | 100%      6|    -     0|    -      0
  src/events/reaction/handleRobotFaceReaction.ts                           |98.3%     59| 100%     2|94.4%     18
  src/events/reaction/index.ts                                             | 100%      4| 100%     1|    -      0