Specify install location for k0s

The machine I am trying to install k0s on has a read-only /usr partition
This causes the install command for k0s to fail

```
executing `sudo -s -- install -m 0750 -o root -g root \"/tmp/tmp.lNe2DW8TD2\" \"/usr/local/bin/k0s\
(stderr) install: cannot create regular file '/usr/local/bin/k0s': Read-only file system
```

https://docs.k0sproject.io/v1.28.2+k0s.0/troubleshooting/#k0s-not-working-with-read-only-usr does not seem to address what to do if you can not install the k0s binary in /usr.

Start with the failing install command in the issue and the linked “k0s not working with read-only /usr” troubleshooting page. Trace how the k0s binary destination is selected, then determine the expected alternative install location or configuration and document or support it with a reproducible read-only-/usr case.

Written by the indexing model from the issue text.