[ADD] : add a new style system for file / dir / links

        can be used for define color, icon, font
        can be used for define global style for all files / dirs / links
[ADD] : add IGFD_FileStyleFlags
        - IGFD_FileStyleByTypeFile             mean define style for all files
	- IGFD_FileStyleByTypeDir              mean define style for all dir
	- IGFD_FileStyleByTypeLink             mean define style for all link
	- IGFD_FileStyleByExtention            mean define style by extention, for files or links
	- IGFD_FileStyleByFullName             mean define style for particular file/dir/link full name (filename + extention)
	- IGFD_FileStyleByContainedInFullName  mean define style for file/dir/link when criteria is contained in full name
[BRK] : BREAKING CHANGE :
        - IGFD::FileExtentionInfos become IGFD::FileStyle
        - CPP : ImGuiFileDialog::SetExtentionInfos become ImGuiFileDialog::SetFileStyle
        - CPP : ImGuiFileDialog::GetExtentionInfos become ImGuiFileDialog::GetFileStyle
        - CPP : ImGuiFileDialog::ClearExtentionInfos become ImGuiFileDialog::ClearFilesStyle
        - C   : IGFD_SetExtentionInfos become IGFD_SetFileStyle
        - C   : IGFD_GetExtentionInfos become IGFD_GetFileStyle
        - C   : IGFD_ClearExtentionInfos become IGFD_ClearFilesStyle

Author: aiekick