MSSQL: Add connection timeout setting in configuration page (#58631)

* MSSQL add connection timeout

* add docs

* Update docs and add min value to the timeout setting

docs/sources/datasources/mssql/_index.md

@@ -77,6 +77,10 @@ For example, use `1m` if Microsoft SQL Server writes data every minute.
 
 You can also override this setting in a dashboard panel under its data source options.
 
+### Connection timeout
+
+The **Connection timeout** setting defines the maximum number of seconds to wait for a connection to the database before timing out. Default is 0 for no timeout.
+
 ### Database user permissions
 
 Grafana doesn't validate that a query is safe, and could include any SQL statement.
@@ -119,6 +123,7 @@ datasources:
       maxOpenConns: 0 # Grafana v5.4+
       maxIdleConns: 2 # Grafana v5.4+
       connMaxLifetime: 14400 # Grafana v5.4+
+      connectionTimeout: 0 # Grafana v9.3+
     secureJsonData:
       password: 'Password!'
 ```