[IMP] *: convert to private methods

render, render_template, load, activity_schedule_with_view,
get_website_pages should all be private:
It should not be possible to render an aribtrary template only with
its name or id

Still need to render some qweb views from js so the method
render_template is kept public.
This explains why the website editor still need read access on
ir.ui.view as we want to allow any snippet to be rendered.

addons/web_editor/static/src/js/editor/snippets.editor.js

@@ -1034,7 +1034,7 @@ var SnippetsMenu = Widget.extend({
         }
         this._defLoadSnippets = this._rpc({
             model: 'ir.ui.view',
-            method: 'render_template',
+            method: 'render_public_asset',
             args: [this.options.snippets, {}],
             kwargs: {
                 context: this.options.context,