Reload, but reset on fail

[TheCataliasTNT2k]

Is there a way to reload all templates, which were added though files, but

• only try to do it, without actually changing anything or
• try to do it and reset to the previous (working) configuration on failures?

This would allow for (manual) reloads, which do not break the server, if a template is broken.

E.g. a streamer uses (broadcasts) one template in their live stream and edits another, this should not break the stream, if any template gets messed up in the process.

Maybe keep the actual behaviour and add a second function like described above, named "try_reload" or something, which resets on failures.

One way to do it right now, is to create a new Tera instance and replace the old one, if the new one parses correctly.