String additional parsing tools

[Yuri6037]

In certain text formats we need:

• Trim(const char *chars = " \t\r\n")
• TrimStart(const char *chars = " \t\r\n")
• TrimEnd(const char *chars = " \t\r\n")
• Compare against white space only (IsWhiteSpace()?)
• Compare against nullptr
• String pre-allocation
• Allow constructing a String from ArrayList, Array and ByteBuf