Support recovery and recovery_available

`recovery: true` installs a module to the recovery partition.
`recovery_available: true` makes a module to be available to other
`recovery:true` or `recovery_available: true` modules.

These to are very similar to vendor, vendor_available properties, except
for the target partition.

Bug: 67916654
Bug: 64960723
Test: m -j, toybox_recovery is installed to the recovery/root/sbin
Change-Id: Iaebe0593de16c69fa70de251a61f4d018a251509

cc/compiler.go

@@ -142,6 +142,19 @@ type BaseCompilerProperties struct {
 			// variant of the C/C++ module.
 			Cflags []string
 		}
+		Recovery struct {
+			// list of source files that should only be used in the
+			// recovery variant of the C/C++ module.
+			Srcs []string
+
+			// list of source files that should not be used to
+			// build the recovery variant of the C/C++ module.
+			Exclude_srcs []string
+
+			// List of additional cflags that should be used to build the recovery
+			// variant of the C/C++ module.
+			Cflags []string
+		}
 	}
 
 	Proto struct {