feat: add TextPreference component

[AprilSylph]

Description

• relates to refactor: use Web Components to render features in the control panel #1831
• relates to feat: add CheckboxPreference component #2055

Creates a TextPreferenceElement class and TextPreference shorthand function, for rendering text-type preferences.

Like CheckboxPreference, this doesn't implement any usages of the new component, just the component itself.

Testing steps

1. Pull this branch locally
2. Download and apply this patch to enable rendering the component: text-preference.patch
3. Load the modified addon
4. Open a Tumblr tab, and keep it visible
5. Open the XKit control panel and enable TimeFormat
   • Expected result: The text-type "Format" preference don't look broken
   • Expected result: The text-type "Format" preference is pre-filled with its default value
6. Without copy-pasting, change the "Format" preference from MMM D, YYYY - h:mm A to Do MMM, YYYY
   • Expected result: Changes to the preference are not reflected immediately after every keystroke
   • Expected result: Changes to the preference are reflected when keystrokes stop for a half-second
7. Open the control panel in a new tab
8. Open the preferences for Quick Reblog and Quick Tags
9. Enable responsive design mode
   • Expected result: 🆕 When making the viewport smaller, the labels for text preferences stay on one line, and only the text box shrinks to fit
   • Expected result: 🆕 When making the viewport wider, the width of text preference inputs caps out at ~240px instead of growing infinitely