DBus listen(number<s>) and daemon \-\-number

implement listen method for DBus
listen(number<s>) -> <>::

add \-\-number option to daemon subcommand
- permits starting daemon in anonymous mode with zero or more numbers
- numbers may be added to daemon with listen() and removed with unlisten()

change misleading "dataPath" to `settingsPath` in App.java
- settingsPath=~/.local/share/signal-cli, while dataPath=~/.local/share/signal-cli/data

only use FileLock when necessary in App.java, and unlock when appropriate

update documentation

lib/src/main/java/org/asamk/signal/manager/Manager.java

@@ -94,6 +94,8 @@ public interface Manager extends Closeable {
 
     void checkAccountState() throws IOException;
 
+    SignalAccount getAccount();
+
     Map<String, Pair<String, UUID>> areUsersRegistered(Set<String> numbers) throws IOException;
 
     void updateAccountAttributes(String deviceName) throws IOException;

lib/src/main/java/org/asamk/signal/manager/ManagerImpl.java

@@ -247,6 +247,11 @@ public class ManagerImpl implements Manager {
         return account.getUsername();
     }
 
+    @Override
+    public SignalAccount getAccount() {
+        return account;
+    }
+
     @Override
     public void checkAccountState() throws IOException {
         if (account.getLastReceiveTimestamp() == 0) {

lib/src/main/java/org/asamk/signal/manager/RegistrationManager.java

@@ -116,8 +116,9 @@ public class RegistrationManager implements Closeable {
         return new RegistrationManager(account, pathConfig, serviceConfiguration, userAgent);
     }
 
-    public void register(boolean voiceVerification, String captcha) throws IOException {
+    public void register(boolean voiceVerification, String captchaString) throws IOException {
         final ServiceResponse<RequestVerificationCodeResponse> response;
+        final var captcha = captchaString == null ? null : captchaString.replace("signalcaptcha://", "");
         if (voiceVerification) {
             response = accountManager.requestVoiceVerificationCode(getDefaultLocale(),
                     Optional.fromNullable(captcha),