feat: add xmake support and a default logger

[qudix]

• add default logger, enabled by default; uses plugin internal name for log file name
  • existing loggers will just get overwritten if initialized before F4SE::Init
  • can be disabled if necessary by passing false to F4SE::Init(a_f4se, ...)
• add F4SE:: getters for plugin name, plugin author, and plugin version
  • also includes a getter for the new F4SE api function GetSaveFolderName introduced in 0.7.1
• add shorthand F4SE_* macros for load and preload functions
• add missing include for the __m128 type
  • not sure why this didn't result in a build error before...
• change Version::(w)string function to use . as the default separator, and allow for arbitrary user modification
• add xmake build support