* add thumbnail preview section to attachments
* dont show thumbnail if the image is already shown inline
* update router to pass the `content` to the attachemnts template
* limit attachment preview height to 150px (same as width)
* remove unused css (referance removed in https://github.com/go-gitea/gitea/pull/11141/files#diff-9faae32445ed9673de2830c9fc35e93f44487f0a0068202988adaf00a5bac850L66 )
* dont show divider after edit if no attachemnts
Co-authored-by: James <inbox.dev@jhodges.co.uk>
Co-authored-by: 6543 <6543@obermui.de>
