build,ci: provide (mostly) static builds via nix and burrito

Signed-off-by: Roman Volosatovs <[email protected]>

.github/actions/build-nix/action.yml

@@ -0,0 +1,14 @@
+name: build via Nix
+
+inputs:
+  package:
+    description: package specification to build
+    required: true
+  install-path:
+    description: path within resulting output, from which to install (e.g. `/lib/libhostcore_wasmcloud_native.so`)
+
+runs:
+  using: composite
+  steps:
+  - run: nix build -L '.#${{ inputs.package }}'
+    shell: bash

.github/actions/install-nix/action.yml

@@ -0,0 +1,18 @@
+name: install Nix
+
+inputs:
+  cachixAuthToken:
+    description: auth token for https://app.cachix.org/organization/wasmcloud/cache/wasmcloud
+
+runs:
+  using: composite
+  steps:
+  - uses: DeterminateSystems/nix-installer-action@v2
+    with:
+      extra-conf: |
+        accept-flake-config = true
+  - uses: cachix/cachix-action@v12
+    continue-on-error: true
+    with:
+      name: wasmcloud
+      authToken: '${{ inputs.cachixAuthToken }}'