Add warning about Omnivore shutting down

- Possibility to configure which buttons are shown in the list (see extension settings)
- Delete button can be added to the list (turned off by default)

- Items are being cached locally, improving initial loading time of the popup
- The popup icon shows the success/failure status when adding items via keyboard shortcut

- The label editor is now shown in a modal instead of a "page"
- Style improvements for buttons

- Text fallback will be used if an image cannot be loaded
- Text fallback for images has higher contrast (previously was not very readable on darker backgrounds)
- Updated all technical dependencies

Added keyboard shortcuts for opening the popup and adding the current page/tab to Omnivore

Labels page is no longer accidentally shown during the initial setup

Smaller UI improvements for labels page

- Articles with long titles will not exceed two lines anymore
- The pagination UI is always properly centered now (was aligned to the left on the last page)
- There are fewer fields being fetched for each article (which in theory leads to better performance)
- Already-archived articles can now be unarchived/restored
- The options page looks a bit better and the advanced options are grouped and labeled a bit better
- The options page now has a “Restore defaults” button that restores the advanced options’ default values

- Added pagination to browse beyond the first 10 articles
- 20 articles are being loaded per page (instead of 10)

- Search query can be customized and defaults to "in:inbox"
- Add simple API error handling and empty list state
- API URL can now be customized (for self-hosting Omnivore)
- Improve layout of settings page

Styles are properly loaded again (this time for real!)

- Styles are properly loaded again
- The label editor displays the labels’ colors as dots
- The label editor provides a link to manage all labels on Omnivore

- Show articles’ labels in the list view (thanks to allibragi!)
- Improved styles and added dark mode to the extension settings

- Add a link to the settings page in the popup (if API key is missing)
- Properly keep the popup open on Windows and Linux when pressing CTRL while opening an item

Features:

- Edit labels of items (thanks to [allibragi](https://github.com/allibragi))

Improvements:

- Improve styles on options page
- Use correct text color for loading text and on labels page (was previoulsy dark on dark)

Improve ellipsis logic of long URLs

- Keep item URLs in one line and add ellipsis
- Add hint about missing API key in popup
- Reset the success message on the options page after one second