use single static class for project's internal constants

Constants.cs

public static class Constants
{
    public const string DefaultUserName = "DEFAULT_USER";

    // MB
    public const int MaxFileSize = 250;
    // ms
    public const int DbTimeout = 10000;
    public const int CookieExpireTime = 1000;
        
    public const string DefaultLogPath = @"C:\DAILY_LOGS";
}