feat: add feature flags

Flags allow you to disable certain functionality and compile with only select features to reduce build time.

Resolves #54.

.github/workflows/build.yml

@@ -30,7 +30,13 @@ jobs:
       - name: Check formatting
         run: cargo fmt --check
 
-      - name: Clippy
+      - name: Clippy (base features)
+        uses: actions-rs/clippy-check@v1
+        with:
+          token: ${{ secrets.GITHUB_TOKEN }}
+          args: --no-default-features --features config+json
+
+      - name: Clippy (all features)
         uses: actions-rs/clippy-check@v1
         with:
           token: ${{ secrets.GITHUB_TOKEN }}