docs - add db privileges, update db connection troubleshooting (#30205) (#30369)

docs/README.md

docs/actions/introduction.md

docs/databases/connecting.md

docs/databases/connections/mysql.md

docs/databases/connections/oracle.md

docs/databases/connections/postgresql.md

docs/databases/connections/presto.md

docs/databases/connections/redshift.md

docs/databases/connections/snowflake.md

docs/databases/connections/sparksql.md

docs/databases/connections/sql-server.md

docs/databases/users-roles-privileges.md

docs/troubleshooting-guide/data-permissions.md

docs/troubleshooting-guide/db-connection.md

docs/troubleshooting-guide/sync-fingerprint-scan.md