Add the packaging metadata to build the parity snap (#5496)

* Add the packaging metadata to build the parity snap

* Move the snapcraft.yaml to scripts

scripts/snapcraft.yaml

@@ -0,0 +1,22 @@
+name: parity
+version: master
+summary: Fast, light, robust Ethereum implementation
+description: |
+  Parity's goal is to be the fastest, lightest, and most secure Ethereum
+  client. We are developing Parity using the sophisticated and cutting-edge
+  Rust programming language. Parity is licensed under the GPLv3, and can be
+  used for all your Ethereum needs.
+
+grade: devel
+confinement: strict
+
+apps:
+  parity:
+    command: parity
+    plugs: [network, network-bind]
+
+parts:
+  parity:
+    source: ..
+    plugin: rust
+    build-packages: [g++, libudev-dev, libssl-dev, make, pkg-config]