Grafana Database password encryption

<!-- Please only use this template for submitting feature requests --> **Why is this needed**: Methods how the DB Password is stored are easy hackable if anyone in the org have access to the server. As either it stores in file or in env. If the password. It will be good feature which comes for most monitoring tools. [Add a description of the problem the feature is trying to solve.] **What would you like to be added**: Mainly it solves the problem related to security and vulnerability which can be addressed by the org [Add a brief description of what the feature or enhancement should do.] **Who is this feature for?** The mainly helps for the grafana admin in the org. [Add information on what kind of user the feature is for.] This is to maintain platform from vulnerability attacks.