Add license and basic documentation

LICENSE:
Add GPL-3.0 license.

{{archiso,configs}/*,.editorconfig,.gitlab-ci.yml}:
Add SPDX license identifier.

Makefile:
Add SPDX license identifier.
Install the `run_archiso.sh` script as global executable `run_archiso`.
Use -D and -t flags to install to install files more generically (without a previous call to install the directory).

README.rst:
Add README outlining the project's scope, how to build images from the profiles and how to test.

AUTHORS.rst:
Add list of all direct contributors to the repository.

CONTRIBUTING.rst:
Add basic contribution guidelines, explaining the linter and the license in use.

Closes #7
Closes #3

8 files changed, 16 insertions, 0 deletions

diff --git a/archiso/initcpio/install/archiso b/archiso/initcpio/install/archiso
index a12104e..3006b5f 100644
--- a/archiso/initcpio/install/archiso
+++ b/archiso/initcpio/install/archiso
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_module "cdrom"
diff --git a/archiso/initcpio/install/archiso_kms b/archiso/initcpio/install/archiso_kms
index 48832ff..8129127 100644
--- a/archiso/initcpio/install/archiso_kms
+++ b/archiso/initcpio/install/archiso_kms
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_module "amdgpu"
diff --git a/archiso/initcpio/install/archiso_loop_mnt b/archiso/initcpio/install/archiso_loop_mnt
index 4a5824d..1f2c529 100644
--- a/archiso/initcpio/install/archiso_loop_mnt
+++ b/archiso/initcpio/install/archiso_loop_mnt
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_runscript
diff --git a/archiso/initcpio/install/archiso_pxe_common b/archiso/initcpio/install/archiso_pxe_common
index da5f6b6..458fa69 100644
--- a/archiso/initcpio/install/archiso_pxe_common
+++ b/archiso/initcpio/install/archiso_pxe_common
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_checked_modules -f "(irda|phy|wimax|wireless|ppp_|plip|pppoe)" "/drivers/net/"
diff --git a/archiso/initcpio/install/archiso_pxe_http b/archiso/initcpio/install/archiso_pxe_http
index 3353eb7..1e80852 100644
--- a/archiso/initcpio/install/archiso_pxe_http
+++ b/archiso/initcpio/install/archiso_pxe_http
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_runscript
diff --git a/archiso/initcpio/install/archiso_pxe_nbd b/archiso/initcpio/install/archiso_pxe_nbd
index 9fe3fdd..b4fb3b6 100644
--- a/archiso/initcpio/install/archiso_pxe_nbd
+++ b/archiso/initcpio/install/archiso_pxe_nbd
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_module "nbd"
diff --git a/archiso/initcpio/install/archiso_pxe_nfs b/archiso/initcpio/install/archiso_pxe_nfs
index fa4e548..efd609d 100644
--- a/archiso/initcpio/install/archiso_pxe_nfs
+++ b/archiso/initcpio/install/archiso_pxe_nfs
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_module "nfs"
diff --git a/archiso/initcpio/install/archiso_shutdown b/archiso/initcpio/install/archiso_shutdown
index 1051d1b..b2c6bd4 100644
--- a/archiso/initcpio/install/archiso_shutdown
+++ b/archiso/initcpio/install/archiso_shutdown
@@ -1,4 +1,6 @@
 #!/usr/bin/env bash
+#
+# SPDX-License-Identifier: GPL-3.0-or-later
 
 build() {
     add_binary cp