feat: useReducer for dataset creation

[AAfghahi]

SUMMARY

This creates the basic reducer hook for the Dataset Creation screen that is currently in process of being implemented.

More actions will be added, but this should be considered the skeleton of the reducer.

Most important to note is the hierarchical nature of the selection actions, database selection should flush tables and schemas, schema selection should do tables, etc.

BEFORE/AFTER SCREENSHOTS OR ANIMATED GIF

TESTING INSTRUCTIONS

ADDITIONAL INFORMATION

• Has associated issue:
• Required feature flags:
• Changes UI
• Includes DB Migration (follow approval process in SIP-59)
  • Migration is atomic, supports rollback & is backwards-compatible
  • Confirm DB migration upgrade and downgrade tested
  • Runtime estimates and downtime expectations provided
• Introduces new feature or API
• Removes existing feature or API

[codecov]

Codecov Report

Merging #20945 (02e0c2c) into master (9350bba) will decrease coverage by 0.00%.
The diff coverage is 0.00%.

❗ Current head 02e0c2c differs from pull request most recent head c4e06ea. Consider uploading reports for the commit c4e06ea to get more accurate results

@@            Coverage Diff             @@
##           master   #20945      +/-   ##
==========================================
- Coverage   66.34%   66.33%   -0.01%     
==========================================
  Files        1767     1767              
  Lines       67286    67295       +9     
  Branches     7140     7144       +4     
==========================================
  Hits        44643    44643              
- Misses      20816    20824       +8     
- Partials     1827     1828       +1     

Flag	Coverage Δ
javascript	52.10% <0.00%> (-0.02%)	⬇️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
.../src/views/CRUD/data/dataset/DatasetPage/index.tsx	0.00% <0.00%> (ø)
...ntend/src/explore/components/ExploreChartPanel.jsx	67.60% <0.00%> (-1.41%)	⬇️
.../explore/components/ExploreViewContainer/index.jsx	52.45% <0.00%> (+0.26%)	⬆️

📣 Codecov can now indicate which changes are the most critical in Pull Requests. Learn more

[eschutho]

LGTM