Revert "Removes timeout script so CI does not have false positives"

This reverts commit c3ed0a1ef9.

ci/build-ignore-timeouts.sh

@@ -0,0 +1,29 @@
+#!/bin/bash -x
+
+output=$(mktemp)
+
+mkdir -p book/
+cp -r $HOME/linkcheck/ book/
+RUST_LOG=mdbook_linkcheck=debug mdbook-linkcheck -s 2>&1 | tee -a $output
+cp -r book/linkcheck $HOME/
+
+mdbook build
+
+result=${PIPESTATUS[0]}
+
+# if passed, great!
+if [ "$result" -eq "0" ] ; then
+    exit 0 ;
+fi
+
+errors=$(cat $output | sed -n 's/There \(was\|were\) \([0-9]\+\).*$/\2/p')
+timeouts=$(cat $output | grep "error while fetching" | wc -l)
+
+# if all errors are timeouts, ignore them...
+if [ "$errors" -eq "$timeouts" ] ; then
+    echo "Ignoring $timeouts timeouts";
+    exit 0;
+else
+    echo "Non-timeout errors found";
+    exit 1;
+fi