Hello Stanislav Mitov !

Yes, you may create own modules/boonex/[your template]/data/template/system/_sub_header.html and _sub_footer.html files and add the banner code before and after this div:

<div class="bx-page-wrapper bx-def-centered bx-def-padding-sec-leftright bx-def-page-width bx-def-box-sizing">

But it's better to use special mod for this.