Refactors Calibre Wireless Device & Calibre Library (#404)

Our esp32 consistently dropped the last few packets of the TCP transfer
in the old implementation. Only about 1/5 transfers would complete. I've
refactored that entire system into an actual Calibre Device Plugin that
basically uses the exact same system as the web server's file transfer
protocol. I kept them separate so that we don't muddy up the existing
file transfer stuff even if it's basically the same at the end of the
day I didn't want to limit our ability to change it later.

I've also added basic auth to OPDS and renamed that feature to OPDS
Browser to just disassociate it from Calibre.

---------

Co-authored-by: Arthur Tazhitdinov <lisnake@gmail.com>
Co-authored-by: Dave Allie <dave@daveallie.com>

src/activities/home/HomeActivity.cpp

@@ -502,8 +502,8 @@ void HomeActivity::render() {
   // Build menu items dynamically
   std::vector<const char*> menuItems = {"My Library", "File Transfer", "Settings"};
   if (hasOpdsUrl) {
-    // Insert Calibre Library after My Library
-    menuItems.insert(menuItems.begin() + 1, "Calibre Library");
+    // Insert OPDS Browser after My Library
+    menuItems.insert(menuItems.begin() + 1, "OPDS Browser");
   }
 
   const int menuTileWidth = pageWidth - 2 * margin;