treewide: add license header and enable haslicense linter

Change-Id: I873a8d4082d75e8f813d8a726a41187eea7a065e
Reviewed-on: https://review.monogon.dev/c/monogon/+/3825
Tested-by: Jenkins CI
Reviewed-by: Leopold Schabel <leo@monogon.tech>
diff --git a/go/net/psample/psample_test.go b/go/net/psample/psample_test.go
index b01ad97..6be8b4e 100644
--- a/go/net/psample/psample_test.go
+++ b/go/net/psample/psample_test.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 // This test requires the following Linux kernel configuration options to be
 // set:
 //
diff --git a/go/net/psample/subscriber.go b/go/net/psample/subscriber.go
index 6e05b9c..d3532a3 100644
--- a/go/net/psample/subscriber.go
+++ b/go/net/psample/subscriber.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 // Package psample provides a receiver for sampled network packets using the
 // Netlink psample interface.
 package psample
diff --git a/go/net/ssh/ssh_client.go b/go/net/ssh/ssh_client.go
index d0a0518..73974d3 100644
--- a/go/net/ssh/ssh_client.go
+++ b/go/net/ssh/ssh_client.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package ssh
 
 import (
diff --git a/go/net/tinylb/connection_pool.go b/go/net/tinylb/connection_pool.go
index 405dd1d..53b0167 100644
--- a/go/net/tinylb/connection_pool.go
+++ b/go/net/tinylb/connection_pool.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package tinylb
 
 import (
diff --git a/go/net/tinylb/tinylb.go b/go/net/tinylb/tinylb.go
index 439628e..3ca6b36 100644
--- a/go/net/tinylb/tinylb.go
+++ b/go/net/tinylb/tinylb.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 // Package tinylb implements a small and simple userland round-robin load
 // balancer, mostly for TCP connections. However, it is entirely
 // protocol-agnostic, and only expects net.Listener and net.Conn objects.
diff --git a/go/net/tinylb/tinylb_test.go b/go/net/tinylb/tinylb_test.go
index 5b7fb16..1cfb46e 100644
--- a/go/net/tinylb/tinylb_test.go
+++ b/go/net/tinylb/tinylb_test.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package tinylb
 
 import (