Bug 35570: (QA follow-up): Follow QA script on Standard backend

Bug 35570: (QA follow-up): Follow QA script on Standard backend

Make QA script green, fix:
- Variables declared in condition
- Use of DateTime->now should certainly be replaced with dt_from_string (bug 24840)
- missing_filter
- forbidden pattern: Do not use line breaks inside template tags (bug 18675)
- Attribute type should not be used for script tags (bug 20053)
- File must have the exec flag
- forbidden pattern: trailing space char
- valid_template: /shared-includes/custom_fields.inc: not found

Signed-off-by: David Nind <david@davidnind.com>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>