Add Risk configuration manager

[eskour]

• Add Risk configuration manager endpoints.
• Add a new table for accommodating the rule lookup names.
• Implement a TValidator when registering a rule for proper configuration validation.
• Migrations scripts for creating additional table:

CREATE TABLE [config].[AppSetting](
    [Key] [nvarchar](512) NOT NULL,
    [Value] [nvarchar](2048) NOT NULL,
 CONSTRAINT [PK_AppSetting] PRIMARY KEY CLUSTERED 
(
    [Key] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY]
GO