Add removeContact command

Closes #335

src/main/java/org/asamk/signal/commands/RemoveContactCommand.java

@@ -0,0 +1,49 @@
+package org.asamk.signal.commands;
+
+import net.sourceforge.argparse4j.impl.Arguments;
+import net.sourceforge.argparse4j.inf.Namespace;
+import net.sourceforge.argparse4j.inf.Subparser;
+
+import org.asamk.signal.commands.exceptions.CommandException;
+import org.asamk.signal.commands.exceptions.IOErrorException;
+import org.asamk.signal.manager.Manager;
+import org.asamk.signal.output.OutputWriter;
+import org.asamk.signal.util.CommandUtil;
+
+import java.io.IOException;
+
+public class RemoveContactCommand implements JsonRpcLocalCommand {
+
+    @Override
+    public String getName() {
+        return "removeContact";
+    }
+
+    @Override
+    public void attachToSubparser(final Subparser subparser) {
+        subparser.help("Remove the details of a given contact");
+        subparser.addArgument("recipient").help("Contact number");
+        subparser.addArgument("--forget")
+                .action(Arguments.storeTrue())
+                .help("Delete all data associated with this contact, including identity keys and sessions.");
+    }
+
+    @Override
+    public void handleCommand(
+            final Namespace ns, final Manager m, final OutputWriter outputWriter
+    ) throws CommandException {
+        var recipientString = ns.getString("recipient");
+        var recipient = CommandUtil.getSingleRecipientIdentifier(recipientString, m.getSelfNumber());
+
+        var forget = Boolean.TRUE == ns.getBoolean("forget");
+        try {
+            if (forget) {
+                m.deleteRecipient(recipient);
+            } else {
+                m.deleteContact(recipient);
+            }
+        } catch (IOException e) {
+            throw new IOErrorException("Remove contact error: " + e.getMessage(), e);
+        }
+    }
+}