Add Terraform and Linux questions and exercises

Also updated the script that counts questions to actually update
the number in README.md

scripts/count_questions.sh

@@ -1,3 +1,9 @@
 #!/usr/bin/env bash
 
-echo $(( $(grep -E "\[Exercise\]|</summary>" -c README.md topics/*/README.md | awk -F: '{ s+=$2 } END { print s }' )))
+set -eu
+
+count=$(echo $(( $(grep -E "\[Exercise\]|</summary>" -c README.md topics/*/README.md | awk -F: '{ s+=$2 } END { print s }' ))))
+
+echo "There are $count questions and exercises"
+
+sed -i "s/currently \*\*[0-9]*\*\*/currently \*\*$count\\**/" README.md