Rename package to revealjs.ids

Renames the fork so the IDS corporate design edition can be installed
alongside upstream rstudio/revealjs (same pattern as posterdown.ids).
Use revealjs.ids::revealjs_presentation in the R Markdown yaml header.

Changes: DESCRIPTION (Package name, Version -> 0.9.1.9009, Title notes
the IDS edition), R/utils.R package lookups, skeleton + RStudio
template identity (now 'Reveal.js Presentation (IDS CD theme)'),
README usage, GitLab CI render call, tests, examples. Old documents
referring to revealjs::revealjs_presentation need upstream revealjs
or a search/replace of the prefix.

Change-Id: Id3988b2c3fd348faca3c0951223d0b90c01741dc
diff --git a/tests/manual/test-incremental-pausing.Rmd b/tests/manual/test-incremental-pausing.Rmd
index 48174db..0da11f5 100644
--- a/tests/manual/test-incremental-pausing.Rmd
+++ b/tests/manual/test-incremental-pausing.Rmd
@@ -1,6 +1,6 @@
 ---
 title: "Incremental by pausing"
-output: revealjs::revealjs_presentation
+output: revealjs.ids::revealjs_presentation
 ---
 
 # Pausing using pandoc syntax