Templating should not fail if `<<` or `>>` are in the template

/kind bug

Our templating should not fail on input like this:

```
echo "<< .FooVersion >>" >> output.log
```
At the moment this seems to be the case. See https://github.com/SovereignCloudStack/csctl/pull/97#issuecomment-1999069161

# TODO
- [ ] fix bug
- [ ] write unit-test
