refactor: Move search and filter logic to a separate module

[lj3954]

Pull Request

Title

Move filter and search logic to another module

Type of Change

• [x] New feature
• [x] Refactoring
• [x] UI/UX improvement

Description

Move all logic related to search and filtering to a separate module, which AppState calls upon. Replace 'search.rs' with 'filter.rs' to better enumerate the logic contained within. Additionally, add the cursor to the search bar (#176), with fixes for panics with multibyte unicode characters & incorrect cursor positioning with characters taking up a non-singular amount of columns.

Testing

Search functions correctly, searchbar and cursor are rendered correctly.

Impact

Improves code structure & readability

• Closes #176 (includes cursor functionality)

Checklist

• [x] My code adheres to the coding and style guidelines of the project.
• [x] I have performed a self-review of my own code.
• [x] My changes generate no errors/warnings/merge conflicts.

[afonsofrancof]

Looks good. I just have a question. Why did you choose the names filter.rs and FilterContent? I know search is used to filter items from the commands list, but it seems weird to call the whole search bar a filter, and call methods such as filter.draw(), which are actually drawing the search bar.

[lj3954]

The logic for filtering entries, regardless of whether or not a search query is present, was moved to the file. It encapsulates significantly more than just search. Perhaps the draw() function should be renamed to draw_searchbar() or something of the like.