A Pack of Improvements

[tfuxu]

This is a pack of miscellaneous improvements and fixes I've made to refresh my Rust knowledge, and to remind myself how fun it is to fight the borrow checker :^)

This pack contains the following changes:

• Added Adw.ToastOverlay container for use in bookmark/clipboard operations
• Put Download and Input views in Adw.Clamp to make them width more dynamic
• Fixed a bug in gemini library that created malformed URLs if the site redirected to relative URL location (fixes #91)
• Fixed an mistake in gemini that put 10000 seconds of timeout on server response
• Removed Pointer_* accelerators (if they were supposed to show gestures, I can add proper accelerators later)
• Removed bottom main menu button (as in most of the app I've seen, they don't move this button to the bottom) (indirectly fixes #54)
• Made upper main menu button primary (enables F10 shortcut)

[ranfdev]

I've merged everything offline, via git, instead of using the github UI. These are some great improvements, thanks!