feat: create dedicated os.d dir for os specific install

bootstrap.bash

@@ -1,6 +1,6 @@
 #!/bin/bash
 
-bash system-ubuntu.bash
+bash os.bash
 bash tools.bash
 bash fonts.bash
 bash config.bash

os.bash

@@ -0,0 +1,5 @@
+#!/bin/bash
+
+for file in os.d/*.bash; do
+  bash $file
+done

os.d/ubuntu.bash

@@ -1,7 +1,6 @@
 #!/bin/bash
 
-if ( grep -q Ubuntu <(lsb_release -i) )
-then
+if (grep -q Ubuntu <(lsb_release -i)); then
     sudo apt update
     sudo apt upgrade -y