moved template resources in own directory inside images

lectures/build.gradle

lectures/revealjs/course-intro.adoc

...s/revealjs/images/lecture01/qrcode-group-registration.svg

lectures/revealjs/images/lecture01/teamwork.png

lectures/revealjs/images/template/hovedlogo_eng.png

lectures/revealjs/images/template/logo_ntnu.png

...ures/revealjs/images/template/logo_ntnu_u-slagord_neg.png

lectures/revealjs/images/template/main_logo_eng.png

lectures/revealjs/images/template/main_logo_eng_no_text.png

lectures/revealjs/images/template/tekst-en.jpg

lectures/revealjs/images/template/vertical-ntnu-name.jpg