batocera-wine: fix save_install() - Wine refused to work then

[crcerror]

• Renamed save_install() -> saveFileToUserdata()
• fixed mv and symlinking to SAVES_WINDIR, would return 1 and therefore WINE did refuse to work
• Added remarks for better mantaining the script

Thanks @aderumier for the WINE-Save idea
@nadenislamarre please review

old PR -> #13656

[nadenislamarre]

there is no error control ?

" cp -r "${WINE_SAVEDIR}/." "${SYSTEM_SAVEDIR}" " for example ?
(ok it was like it before...)

[crcerror]

Well there is an error-control. The function is introduced with:
fileSavesToUserdata || return 1
And it works.... the old script tried to move or link into the SYSTEM_SAVEDIR for example and failed. This leaded to refuse the start of WINE. The error-control could be better .... but I think we should have a 80% good working script now.