add astra1.7

platforms.json

@@ -1,5 +1,21 @@
 {
   "Platforms": {
+    "Astra Linux 1.7": {
+      "enabled": true,
+      "ondemand": true,
+      "codename": "astra1.7",
+      "docker_dir": "astra1.7",
+      "docker_image": "astra1.7",
+      "docker_build_options": {
+        "image_from": "debian:buster-slim",
+        "image_prepare_script": "install_apt.sh"
+      },
+      "ppa_filters": ["astra1.7"],
+      "ppa_instructions": [
+        "wget -qO - https://ppa.${domain}/SHS.gpg | sudo apt-key add -",
+        "echo \"deb https://ppa.${domain}/ ${codename} main\" | sudo tee /etc/apt/sources.list.d/SHS.list"
+      ]
+    },
     "Debian 10": {
       "enabled": true,
       "codename": "buster",