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.

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

src/activities/network/CrossPointWebServerActivity.h

@@ -23,7 +23,7 @@ enum class WebServerActivityState {
 /**
  * CrossPointWebServerActivity is the entry point for file transfer functionality.
  * It:
- * - First presents a choice between "Join a Network" (STA) and "Create Hotspot" (AP)
+ * - First presents a choice between "Join a Network" (STA), "Connect to Calibre", and "Create Hotspot" (AP)
  * - For STA mode: Launches WifiSelectionActivity to connect to an existing network
  * - For AP mode: Creates an Access Point that clients can connect to
  * - Starts the CrossPointWebServer when connected