Add template for presentation

The template allows to quicly start a presentation
that makes use of the include directive to get the header and footer
relevant to the NTNU theme

lectures/revealjs/template.adoc

+= Title here
+:customcss: slides.css
+:icons: font
+:includedir: revealjs/includes/
+:LECTURE_TOPIC: Topic
+:LECTURE_NO: Nth lecture
+
+include::{includedir}header.adoc[]
+
+
+[.smaller-80][.center-paragraph]
+IT1901 Fall 2020 - {LECTURE_NO}
+
+[background-color = "#124990"]
+[color = "#fff6d5"]
+== Section slide
+
+== Normal slide
+
+- Blah
+- Foo
+- Bar
+
+[.grid-left-right-50-50]
+== 2 column slide 
+
+[.area-left]
+- blah blah cloud
+** foo
+** bar
+** baz
+
+[.area-right]
+- blah blah cloud
+** right foo
+** right bar
+** righ baz
+
+
+include::{includedir}footer.adoc[]
\ No newline at end of file