plots: load templates from package (iterative#6550)

* plots: vega: make interactive linear default plot

* plots: stop dumping default templates

* plots: move templates to package initial

* plots: update default plots schema

* plots: write defaults on init

* templates: migrate to importlib.resources

* fixup

* fixup

MANIFEST.in

@@ -1 +1,3 @@
 include LICENSE
+recursive-include requirements *.txt
+recursive-include dvc/repo/plots/templates *.json

dvc/render/utils.py

@@ -1,7 +1,7 @@
 import os.path
 from typing import Dict, List
 
-import dpath
+import dpath.util
 
 
 def get_files(data: Dict) -> List:

dvc/render/vega.py

@@ -147,7 +147,7 @@ def _datapoints(self, props: Dict):
     def get_vega(self) -> Optional[str]:
         props = self._squash_props()
 
-        template = self.templates.load(props.get("template") or "default")
+        template = self.templates.load(props.get("template", None))
 
         if not props.get("x") and template.has_anchor("x"):
             props["append_index"] = True

dvc/repo/plots/__init__.py

@@ -161,7 +161,7 @@ def modify(self, path, props=None, unset=None):
         props = props or {}
         template = props.get("template")
         if template:
-            self.templates.get_template(template)
+            self.templates.load(template)
 
         (out,) = self.repo.find_outs_by_path(path)
         if not out.plot and unset is not None: