Change texterify_timestamp in exports to "last edited"

[mbuchetics]

Currently, texterify_timestamp represents the time whenever your strings were exported. This often leads to unnecessary merge conflicts if files are exported but nothing besides the timestamp has changed. I would like to omit this timestamp and replace it with a value that represents the time the strings were last changed.

[weakfl]

+1

Would like to skip this altogether if possible. It's just useless noise causing conflicts.