Mark databricks_sql_dashaboard as deprecated (#4641)

## Changes
<!-- Summary of your changes that are easy to understand -->

Also added corresponding warnings to documentation for `sql_query` and
`sql_alert`


## Tests
<!-- 
How is this tested? Please see the checklist below and also describe any
other relevant tests
-->

- [x] `make test` run locally
- [x] relevant change in `docs/` folder
- [ ] covered with integration tests in `internal/acceptance`
- [ ] using Go SDK
- [ ] using TF Plugin Framework

Author: alexott

NEXT_CHANGELOG.md

@@ -4,6 +4,7 @@
 
 ### New Features and Improvements
 
+ * Mark `databricks_sql_dashaboard` as deprecated ([#4641](https://github.com/databricks/terraform-provider-databricks/pull/4641))
  * Add a new settings resource `databricks_disable_legacy_dbfs_setting` ([#4605](https://github.com/databricks/terraform-provider-databricks/pull/4605))
 
 ### Bug Fixes

docs/resources/sql_alert.md

@@ -3,6 +3,8 @@ subcategory: "Databricks SQL"
 ---
 # databricks_sql_alert Resource
 
+!> This resource is deprecated! Please switch to [databricks_alert](alert.md#migrating-from-databricks_sql_alert-resource).
+
 This resource allows you to manage [Databricks SQL Alerts](https://docs.databricks.com/sql/user/queries/index.html).
 
 -> To manage [SQLA resources](https://docs.databricks.com/sql/get-started/concepts.html) you must have `databricks_sql_access` on your [databricks_group](group.md#databricks_sql_access) or [databricks_user](user.md#databricks_sql_access).

docs/resources/sql_dashboard.md

@@ -3,11 +3,10 @@ subcategory: "Databricks SQL"
 ---
 # databricks_sql_dashboard Resource
 
--> Please switch to [databricks_dashboard](dashboard.md) to author new AI/BI dashboards using the latest tooling.
+!> This resource is deprecated! Please switch to [databricks_dashboard](dashboard.md) to author new AI/BI dashboards using the latest tooling.
 
 This resource is used to manage [Legacy dashboards](https://docs.databricks.com/sql/user/dashboards/index.html). To manage [SQL resources](https://docs.databricks.com/sql/get-started/concepts.html) you must have `databricks_sql_access` on your [databricks_group](group.md#databricks_sql_access) or [databricks_user](user.md#databricks_sql_access).
 
-
 -> documentation for this resource is a work in progress.
 
 A dashboard may have one or more [widgets](sql_widget.md).

docs/resources/sql_query.md

@@ -3,6 +3,8 @@ subcategory: "Databricks SQL"
 ---
 # databricks_sql_query Resource
 
+!> This resource is deprecated! Please switch to [databricks_query](query.md#migrating-from-databricks_sql_query-resource).
+
 To manage [SQLA resources](https://docs.databricks.com/sql/get-started/concepts.html) you must have `databricks_sql_access` on your [databricks_group](group.md#databricks_sql_access) or [databricks_user](user.md#databricks_sql_access).
 
 -> documentation for this resource is a work in progress.

sql/resource_sql_dashboard.go

@@ -102,6 +102,7 @@ func ResourceSqlDashboard() common.Resource {
 		common.NoCustomize)
 
 	return common.Resource{
+		DeprecationMessage: "This resource is deprecated and will be removed in the future. Please use the `databricks_dashboard` resource.",
 		Create: func(ctx context.Context, data *schema.ResourceData, c *common.DatabricksClient) error {
 			var d DashboardEntity
 			ad, err := d.toAPIObject(s, data)