Add new Button on Course Page to Add Course to Planner

[EssWhyy]

Context

Implementation for #3399

Implementation

Added a button to each module page to allow a user to save the module to the planner in the Plan to Take section, acting like a save button of sorts.

If it is already added to Plan To Take, the button will remove the module from there instead.

Test Run:

https://github.com/nusmodifications/nusmods/assets/39799639/bb7ccd98-f413-4400-9ca1-12440988319b

Other Information

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[codecov[bot]]

Codecov Report

Attention: Patch coverage is 51.21951% with 20 lines in your changes missing coverage. Please review.

Project coverage is 53.62%. Comparing base (7334b07) to head (884b76b). Report is 16 commits behind head on master.

Files	Patch %	Lines
.../views/components/module-info/SaveModuleButton.tsx	48.71%	20 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #3731 +/- ## ======================================= Coverage 53.62% 53.62% ======================================= Files 272 273 +1 Lines 5979 6020 +41 Branches 1428 1437 +9 ======================================= + Hits 3206 3228 +22 - Misses 2773 2792 +19 ```

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