feat: improve feed directory UI with default parameter handling

[gildesmarais]

This pull request refines the feed directory UI and improves the parameter configuration experience. The main changes include a more compact and visually consistent list layout, a new toggle button for configuring feed parameters, and improved initialization of default parameter values in the JavaScript logic.

UI/UX improvements:

• Updated .feed-directory__item styles for a more compact, consistent appearance, including changing alignment, adding a subtle background, and reducing spacing between items.
• Added .feed-directory__item-main and .feed-directory__item-param-toggle classes to create a new flex container for the feed name and parameter toggle button, improving layout and accessibility.
• Enhanced the parameter form styling with a background, rounded corners, and a slide-down animation for smoother transitions.
• Reworked the feed item HTML structure to include the new parameter toggle button and icon, and removed the old settings button for a cleaner interface. [1] [2] [3]

JavaScript improvements:

• Added initializeDefaultParameters() to set default parameter values in input fields and state, ensuring a smoother user experience when configuring feeds.