multi: pass private, routehints from loopcli - loopd - loop server

This commit passes routehints all the way from when/if the user passes
them from the cli all the way to the backend loop server. If private is
used, this commit passes that boolean down to different stages, where it
is then converted into routehints.

main: add --private and --route_hints to quote

Adds --private and --route_hints flags to quote cli

interface.go

@@ -207,6 +207,15 @@ type LoopInRequest struct {
 	// initiated the swap (loop CLI, autolooper, LiT UI and so on) and is
 	// appended to the user agent string.
 	Initiator string
+
+	// Private indicates whether the destination node should be considered
+	// private. In which case, loop will generate hophints to assist with
+	// probing and payment.
+	Private bool
+
+	// RouteHints are optional route hints to reach the destination through
+	// private channels.
+	RouteHints [][]zpay32.HopHint
 }
 
 // LoopInTerms are the server terms on which it executes loop in swaps.
@@ -253,6 +262,11 @@ type LoopInQuoteRequest struct {
 	// RouteHints are optional route hints to reach the destination through
 	// private channels.
 	RouteHints [][]zpay32.HopHint
+
+	// Private indicates whether the destination node should be considered
+	// private. In which case, loop will generate hophints to assist with
+	// probing and payment.
+	Private bool
 }
 
 // LoopInQuote contains estimates for the fees making up the total swap cost