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/R/revealjs_presentation.R b/R/revealjs_presentation.R
index 8d1c9d8..bdc4153 100644
--- a/R/revealjs_presentation.R
+++ b/R/revealjs_presentation.R
@@ -119,7 +119,7 @@
 #' \dontrun{
 #'
 #' library(rmarkdown)
-#' library(revealjs)
+#' library(revealjs.ids)
 #'
 #' # simple invocation
 #' render("pres.Rmd", revealjs_presentation())