* lisp/progmodes/sql.el: Added password wallet using

* lisp/progmodes/sql.el: Added password wallet using
`auth-source' package.
(sql-auth-source-search-wallet): New function.
(sql-password-wallet): New variable.
(sql-password-search-wallet-function): New variable.
(sql-get-login): Handle password wallet search.
(sql-product-interactive): Handle password function.
* test/lisp/progmodes/sql-test.el: Test wallet changes.
(sql-test-login-params): New test variable.
(with-sql-test-connect-harness): New macro to wrap test
configuration around calls to `sql-connect'.
(sql-test-connect, sql-test-connect-password-func)
(sql-test-connect-wallet-server-database)
(sql-test-connect-wallet-database)
(sql-test-connect-wallet-server): New ERT tests.
* etc/NEWS: Updated SQL Mode descriptions.