move /app/code/template-extension to /app/data

[luckow]

If you install https://piwigo.org/ext/extension_view.php?eid=144 as a plugin, you cannot edit the files because the file system is read-only.

[robi]

@luckow how does it install if it's read only?

[nebulon]

yes, we could link that folder, but it is unclear to me what exactly goes there and if this is properly supported during upstream updates. Mostly also because that folder already contains php files which are part of the upstream release, so I am bit hesitant to put them into /app/data without a known way to potentially upgrade them.