[rebrand][posix] rename homedir, env vars and log file

- rename userdata dir dynamically determined application name(via CCompileInfo::GetAppName())
  -> .kodi
- rename XBMC_HOME to APP_HOME on posix platforms
- rename the log file to dynamically determined application name(via CCompileInfo::GetAppName())
  on all platforms
  -> kodi.log
[rebrand] adjust xrandr to use dynamic application name
[rebrand][darwin] adjust to new env var APP_HOME instead of XBMC_HOME
[rebrand][android] adjust to new env var APP_HOME instead of XBMC_HOME
[rebrand][linux] adjust to new env var APP_HOME instead of XBMC_HOME