Introduce @SqlConfig for common SQL script config

Prior to this commit, @Sql provided attributes for configuring the
syntax of the referenced SQL scripts as well as exception handling and
transaction behavior; however, such configuration could not be reused
across @Sql declarations thus requiring developers to copy-and-paste
common configuration and resulting in unnecessary code duplication.

This commit addresses this issue by introducing a new @SqlConfig
annotation that can be used to declare common, global configuration for
SQL scripts that can be reused within a test class hierarchy.

 - Introduced top-level @SqlConfig annotation and extracted
   common configuration attributes from @Sql.

 - @SqlConfig can be used at the class level for common, global config
   or via the new 'config' attribute of @Sql for local config.

 - Introduced MergedSqlConfig as a holder for the merged values from
   local and global @SqlConfig instances. MergedSqlConfig also contains
   the logic for overriding global configuration with local
   configuration.

 - Refactored all attributes of @SqlConfig to be either of type String
   or custom enums in order to support overriding. Empty Strings or
   DEFAULT enum values imply the use of a default or inherited value.

Issue: SPR-11896
Merge from sbrannen/SPR-11896

* SPR-11896:
  Introduce @SqlConfig for common SQL script config