Split command into process and adb

The process API provides the system-specific implementation, the adb API
uses it to expose adb commands.

app/src/adb.h

@@ -0,0 +1,34 @@
+#ifndef SC_ADB_H
+#define SC_ADB_H
+
+#include <stdbool.h>
+#include <inttypes.h>
+
+#include "config.h"
+
+#include "util/process.h"
+
+process_t
+adb_execute(const char *serial, const char *const adb_cmd[], size_t len);
+
+process_t
+adb_forward(const char *serial, uint16_t local_port,
+            const char *device_socket_name);
+
+process_t
+adb_forward_remove(const char *serial, uint16_t local_port);
+
+process_t
+adb_reverse(const char *serial, const char *device_socket_name,
+            uint16_t local_port);
+
+process_t
+adb_reverse_remove(const char *serial, const char *device_socket_name);
+
+process_t
+adb_push(const char *serial, const char *local, const char *remote);
+
+process_t
+adb_install(const char *serial, const char *local);
+
+#endif