Node code cleanup for vector data, and add node creation guide (#895)

* Cleanup Vector Nodes

* Add the creating nodes guide

* Rename guide as readme so GitHub shows it by default

Co-authored-by: Keavon Chambers <keavon@keavon.com>

node-graph/graph-craft/src/imaginate_input.rs

@@ -1,27 +1,3 @@
-#[cfg(feature = "serde")]
-mod base64_serde {
-	use serde::{Deserialize, Deserializer, Serializer};
-
-	pub fn as_base64<S>(key: &std::sync::Arc<Vec<u8>>, serializer: S) -> Result<S::Ok, S::Error>
-	where
-		S: Serializer,
-	{
-		serializer.serialize_str(&base64::encode(key.as_slice()))
-	}
-
-	pub fn from_base64<'a, D>(deserializer: D) -> Result<std::sync::Arc<Vec<u8>>, D::Error>
-	where
-		D: Deserializer<'a>,
-	{
-		use serde::de::Error;
-
-		String::deserialize(deserializer)
-			.and_then(|string| base64::decode(string).map_err(|err| Error::custom(err.to_string())))
-			.map(std::sync::Arc::new)
-			.map_err(serde::de::Error::custom)
-	}
-}
-
 use dyn_any::{DynAny, StaticType};
 use glam::DVec2;
 use std::fmt::Debug;