Starting to create the renderer integrations.

These are the layer directly over dust which can be used by anything, not just blog posts.

src/render/renderer_integration.rs

@@ -0,0 +1,15 @@
+use std::path::Path;
+use std::path::PathBuf;
+
+use crate::error::CustomError;
+
+pub trait RendererIntegration {
+    fn load_templates<I, P>(&mut self, dust_templates: I) -> Result<(), CustomError>
+    where
+        I: Iterator<Item = P>,
+        P: Into<PathBuf>;
+
+    fn render<P>(&self, context: &str, build_directory: P) -> Result<String, CustomError>
+    where
+        P: AsRef<Path>;
+}