Shorten long file names (r8, r7, r6, r5)

https://review.opendev.org/c/starlingx/docs/+/893405 revealed
a problem with very long file names not being linkable in some
browsing contexts. The problem was corrected by shortening
the filename to 75 chars + extension. This review checks for
and trims long filename input to 'tox -e newfile' to 75 chars
+ extension. (62 + dash + UUID fragment)

Signed-off-by: Ron Stone <ronald.stone@windriver.com>
Change-Id: Id6fa734c664977606649ff38d7e837fd1f91d178
(cherry picked from commit 87cf79ba4c6b48b6a06d9a255943603e3d0e4302)

new-topic.sh

@@ -5,9 +5,11 @@ if ! hash uuidgen 2>/dev/null; then
   exit 1
 fi
 
-INCLUDEDIR="$2/doc/source/_includes"
-
+declare INCLUDEDIR="$2/doc/source/_includes"
 declare -A charReplacements
+# max basename lenght *before* appending UUID
+declare MAX_LEN=62
+
 
 charReplacements=(
    ["-"]="minus"
@@ -128,6 +130,12 @@ do
   filename=`sed "s/$c/${charReplacements[$c]}/g" <<< $filename`
 done
 
+if [[ ${#filename} -gt ${MAX_LEN} ]]; then
+   filename=${filename:0:$MAX_LEN}
+   declare FULL_LEN=$(($MAX_LEN + 13))
+   echo -e "\nFilename and label shortend to $FULL_LEN chars"
+fi
+
 filename="${filename//[^[:alnum:]]/-}"
 filename=$(echo $filename | tr -s -)
 filename="${filename}-${myuuid}"