Add sub-extension to resource files in built-in templates (#1777)

## Changes
We want to encourage a pattern of only specifying a single resource in a
YAML file when an `.<resource-type>.yml` (like `.job.yml`) is used. This
convention could allow us to bijectively map a resource YAML file to
it's corresponding resource in the Databricks workspace.

This PR simply makes the built-in templates compliant to this format.

## Tests
Existing tests.

libs/template/templates/dbt-sql/template/{{.project_name}}/README.md.tmpl

@@ -121,7 +121,7 @@ You can find that job by opening your workpace and clicking on **Workflows**.
 
 You can also deploy to your production target directly from the command-line.
 The warehouse, catalog, and schema for that target are configured in databricks.yml.
-When deploying to this target, note that the default job at resources/{{.project_name}}_job.yml
+When deploying to this target, note that the default job at resources/{{.project_name}}.job.yml
 has a schedule set that runs every day. The schedule is paused when deploying in development mode
 (see https://docs.databricks.com/dev-tools/bundles/deployment-modes.html).
 

libs/template/templates/default-python/template/__preamble.tmpl

@@ -18,7 +18,7 @@ This file only template directives; it is skipped for the actual output.
 
 {{if $notDLT}}
   {{skip "{{.project_name}}/src/dlt_pipeline.ipynb"}}
-  {{skip "{{.project_name}}/resources/{{.project_name}}_pipeline.yml"}}
+  {{skip "{{.project_name}}/resources/{{.project_name}}.pipeline.yml"}}
 {{end}}
 
 {{if $notNotebook}}
@@ -26,7 +26,7 @@ This file only template directives; it is skipped for the actual output.
 {{end}}
 
 {{if (and $notDLT $notNotebook $notPython)}}
-  {{skip "{{.project_name}}/resources/{{.project_name}}_job.yml"}}
+  {{skip "{{.project_name}}/resources/{{.project_name}}.job.yml"}}
 {{else}}
   {{skip "{{.project_name}}/resources/.gitkeep"}}
 {{end}}

libs/template/templates/default-python/template/{{.project_name}}/README.md.tmpl

@@ -29,7 +29,7 @@ The '{{.project_name}}' project was generated by using the default-python templa
    ```
 
    Note that the default job from the template has a schedule that runs every day
-   (defined in resources/{{.project_name}}_job.yml). The schedule
+   (defined in resources/{{.project_name}}.job.yml). The schedule
    is paused when deploying in development mode (see
    https://docs.databricks.com/dev-tools/bundles/deployment-modes.html).
 

libs/template/templates/default-python/template/{{.project_name}}/resources/{{.project_name}}.job.yml.tmpl

@@ -40,7 +40,7 @@ resources:
             - task_key: notebook_task
           {{- end}}
           pipeline_task:
-            {{- /* TODO: we should find a way that doesn't use magics for the below, like ./{{project_name}}_pipeline.yml */}}
+            {{- /* TODO: we should find a way that doesn't use magics for the below, like ./{{project_name}}.pipeline.yml */}}
             pipeline_id: ${resources.pipelines.{{.project_name}}_pipeline.id}
         {{end -}}
         {{- if (eq .include_python "yes") }}

libs/template/templates/default-python/template/{{.project_name}}/src/dlt_pipeline.ipynb.tmpl

@@ -14,7 +14,7 @@
    "source": [
     "# DLT pipeline\n",
     "\n",
-    "This Delta Live Tables (DLT) definition is executed using a pipeline defined in resources/{{.project_name}}_pipeline.yml."
+    "This Delta Live Tables (DLT) definition is executed using a pipeline defined in resources/{{.project_name}}.pipeline.yml."
    ]
   },
   {

libs/template/templates/default-python/template/{{.project_name}}/src/notebook.ipynb.tmpl

@@ -14,7 +14,7 @@
    "source": [
     "# Default notebook\n",
     "\n",
-    "This default notebook is executed using Databricks Workflows as defined in resources/{{.project_name}}_job.yml."
+    "This default notebook is executed using Databricks Workflows as defined in resources/{{.project_name}}.job.yml."
    ]
   },
   {

libs/template/templates/default-sql/template/{{.project_name}}/src/orders_daily.sql.tmpl

@@ -1,4 +1,4 @@
--- This query is executed using Databricks Workflows (see resources/{{.project_name}}_sql_job.yml)
+-- This query is executed using Databricks Workflows (see resources/{{.project_name}}_sql.job.yml)
 
 USE CATALOG {{"{{"}}catalog{{"}}"}};
 USE IDENTIFIER({{"{{"}}schema{{"}}"}});

libs/template/templates/default-sql/template/{{.project_name}}/src/orders_raw.sql.tmpl

@@ -1,4 +1,4 @@
--- This query is executed using Databricks Workflows (see resources/{{.project_name}}_sql_job.yml)
+-- This query is executed using Databricks Workflows (see resources/{{.project_name}}_sql.job.yml)
 --
 -- The streaming table below ingests all JSON files in /databricks-datasets/retail-org/sales_orders/
 -- See also https://docs.databricks.com/sql/language-manual/sql-ref-syntax-ddl-create-streaming-table.html