[C#] allow customization of generated enum suffixes

Created by: scottdallamura

allows customization of enum suffixes for C# addresses #4275

{
    "apiPackage": "RestApi.Controllers",
    "modelPackage": "RestApi.Models",
    "packageName": "RestApi",
    "enumNameSuffix": "aaa",
    "enumValueNameSuffix": "bbb"
}

generates stuff like (not that i would ever want 'aaa' or 'bbb' suffixes, but it's a fine example...)

        /// <summary>
        /// Gets or Sets Status
        /// </summary>
        [TypeConverter(typeof(CustomEnumConverter<Statusaaa>))]
        [JsonConverter(typeof(Newtonsoft.Json.Converters.StringEnumConverter))]
        public enum Statusaaa
        {
            
            /// <summary>
            /// Enum Activebbb for Active
            /// </summary>
            [EnumMember(Value = "Active")]
            Activebbb = 1,
            
            /// <summary>
            /// Enum Disabledbbb for Disabled
            /// </summary>
            [EnumMember(Value = "Disabled")]
            Disabledbbb = 2
        }

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