feat(docs): Add targets to help making local preview docs easier. (#345)

* docs(docs): Add local-docs dev utility target

* fix(docs): dev artifact directory

* docs(docs): Copy the local dev script as a directory

Author: stevenj

earthly/docs/Earthfile

@@ -68,6 +68,21 @@ common:
 
     SAVE ARTIFACT /std
 
+# The file we use for local-docs:
+local-docs:
+    FROM scratch
+
+    COPY --dir dev .
+    SAVE ARTIFACT /dev
+
+# SYNC_STD_CFG : Syncs the standard config files locally.
+SYNC_LOCAL_DOCS:
+    FUNCTION
+    FROM scratch
+    COPY --dir +local-docs/dev /dev
+
+    SAVE ARTIFACT /dev/local.py AS LOCAL local.py
+
 # Common src setup
 SRC:
     FUNCTION