Relates to #38806
Host name templates previously accepted only built-in $FLEET_VAR_*
variables and rejected custom $FLEET_SECRET_* (secret) variables. Allow
secret variables so admins can embed an org-wide custom value in an
Apple host's name.
# Checklist for submitter
If some of the following don't apply, delete the relevant line.
- [X] Input data is properly validated, `SELECT *` is avoided, SQL
injection is prevented (using placeholders for values in statements), JS
inline code is prevented especially for url redirects, and untrusted
data interpolated into shell scripts/commands is validated against shell
metacharacters.
## Testing
- [X] Added/updated automated tests
- [X] QA'd all new/changed functionality manually
Juan Fernandez
89ec4f3abb