[IMP] project: improved stages usability

People tend to click on the gear on the stage column and click
the "Edit" button. There, they think they are creating a task.

- Rename the 'Edit' button into 'Edit Stage'.
- Hide mail_template_id and project_ids fields in technical features.

addons/project/views/project_views.xml

@@ -617,7 +617,7 @@ action = model.activate_sample_project()
                     <group>
                         <group>
                             <field name="name"/>
-                            <field name="mail_template_id"/>
+                            <field name="mail_template_id" groups="base.group_no_one"/>
                         </group>
                         <group>
                             <field name="fold"/>
@@ -648,7 +648,7 @@ action = model.activate_sample_project()
                         </p>
                         <field name="description" placeholder="Add a description..." nolabel="1" colspan="2"/>
                     </group>
-                    <group string="Projects using this stage">
+                    <group string="Projects using this stage" groups="base.group_no_one">
                         <field name="project_ids" widget="many2many_tags"/>
                     </group>
                 </form>

addons/web_kanban/static/src/xml/web_kanban.xml

@@ -18,7 +18,7 @@
                 <ul class="dropdown-menu" role="menu">
                     <li><a class="o_kanban_toggle_fold" href="#">Fold</a></li>
                     <t t-if="widget.grouped_by_m2o">
-                        <li t-if="widget.editable and widget.id"><a class="o_column_edit" href="#">Edit</a></li>
+                        <li t-if="widget.editable and widget.id"><a class="o_column_edit" href="#">Edit Stage</a></li>
                         <li t-if="widget.deletable and widget.id"><a class="o_column_delete" href="#">Delete</a></li>
                     </t>
                     <t t-if="widget.has_active_field">