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/osbase/fat32/dos83.go b/osbase/fat32/dos83.go
index 650df96..1d988be 100644
--- a/osbase/fat32/dos83.go
+++ b/osbase/fat32/dos83.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package fat32
 
 import (
diff --git a/osbase/fat32/fat32.go b/osbase/fat32/fat32.go
index c8d4ec9..e5c2e58 100644
--- a/osbase/fat32/fat32.go
+++ b/osbase/fat32/fat32.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 // Package fat32 implements a writer for the FAT32 filesystem.
 package fat32
 
diff --git a/osbase/fat32/fsck_test.go b/osbase/fat32/fsck_test.go
index 4b5f97d..d4908be 100644
--- a/osbase/fat32/fsck_test.go
+++ b/osbase/fat32/fsck_test.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package fat32
 
 import (
diff --git a/osbase/fat32/linux_test.go b/osbase/fat32/linux_test.go
index 2237f38..ffe7672 100644
--- a/osbase/fat32/linux_test.go
+++ b/osbase/fat32/linux_test.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package fat32
 
 import (
diff --git a/osbase/fat32/structs.go b/osbase/fat32/structs.go
index 396361d..3292798 100644
--- a/osbase/fat32/structs.go
+++ b/osbase/fat32/structs.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package fat32
 
 const (
diff --git a/osbase/fat32/structs_test.go b/osbase/fat32/structs_test.go
index 77a7df0..f361a89 100644
--- a/osbase/fat32/structs_test.go
+++ b/osbase/fat32/structs_test.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package fat32
 
 import (
diff --git a/osbase/fat32/utils.go b/osbase/fat32/utils.go
index 833665c..8ddb162 100644
--- a/osbase/fat32/utils.go
+++ b/osbase/fat32/utils.go
@@ -1,3 +1,6 @@
+// Copyright The Monogon Project Authors.
+// SPDX-License-Identifier: Apache-2.0
+
 package fat32
 
 import (