feat(linux): add librepods-ctl CLI tool for IPC control (#494)

* feat(linux): expanded IPC socket handler with CLI command support

* feat(linux): added librepods-ctl CLI tool for IPC control

* build(linux): added librepods-ctl as a seperate binary

* docs(linux): added CLI control usage to README

linux/librepods-ctl.cpp

@@ -0,0 +1,31 @@
+#include <QCoreApplication>
+#include <QLocalSocket>
+#include <QTextStream>
+
+int main(int argc, char *argv[]) {
+    QCoreApplication app(argc, argv);
+
+    if (argc < 2) {
+        QTextStream(stderr) << "Usage: librepods-ctl <command>\n"
+                            << "Commands:\n"
+                            << "  noise:off           Disable noise control\n"
+                            << "  noise:anc           Enable Active Noise Cancellation\n"
+                            << "  noise:transparency  Enable Transparency mode\n"
+                            << "  noise:adaptive      Enable Adaptive mode\n";
+        return 1;
+    }
+
+    QLocalSocket socket;
+    socket.connectToServer("app_server");
+
+    if (!socket.waitForConnected(500)) {
+        QTextStream(stderr) << "Could not connect to librepods (is it running?)\n";
+        return 1;
+    }
+
+    socket.write(QByteArray(argv[1]));
+    socket.flush();
+    socket.waitForBytesWritten(200);
+    socket.disconnectFromServer();
+    return 0;
+}