selftests.checkall: Improve the readability

This patch adds summary at the end of the execution and uses colors to
mark start and finish of each section. This might produce some
unexpected characters on redirections/unsupported terminals at the
beginning and endings of the highlighted lines, but in most cases it
looks way better and those +3 chars can be ignored by humans.
Signed-off-by: NLukáš Doktor <ldoktor@redhat.com>

selftests/checkall

 #!/bin/bash
-GR=0
+ERR=()
 run_rc() {
-    echo "Running '$1'"
+    CHECK=$1
+    shift
+    echo -e "\n\e[32mRunning '$1'\e[0m"
     eval $1
     if [ $? != 0 ]; then
-        GR=1
+        echo -e "\e[31m$CHECK FAILED\e[0m"
+        ERR+=("$CHECK")
         [ ! "$SELF_CHECK_CONTINUOUS" ] && exit 1
+    else
+        echo -e "\e[32m$CHECK PASSED\e[0m\n"
     fi
 }
-run_rc 'inspekt --exclude=.git lint'
-echo ""
-run_rc 'inspekt --exclude=.git indent'
-echo ""
-run_rc 'inspekt --exclude=.git style'
-echo ""
-run_rc 'selftests/modules_boundaries'
-echo ""
+run_rc lint 'inspekt --exclude=.git lint'
+run_rc indent 'inspekt --exclude=.git indent'
+run_rc style 'inspekt --exclude=.git style'
+run_rc boundaries 'selftests/modules_boundaries'
 if [ -z "$AVOCADO_SELF_CHECK" ]; then
-    run_rc selftests/run
+    run_rc selftests selftests/run
 else
-    run_rc 'scripts/avocado run `./contrib/scripts/avocado-find-unittests selftests/{unit,functional,doc}/*.py | xargs` --external-runner="/usr/bin/env python -m unittest"'
+    run_rc selftests 'scripts/avocado run `./contrib/scripts/avocado-find-unittests selftests/{unit,functional,doc}/*.py | xargs` --external-runner="/usr/bin/env python -m unittest"'
 fi
-exit ${GR}
+
+if [ "$ERR" ]; then
+    echo -e "\e[31m"
+    echo "Checks:"
+    for CHECK in "${ERR[@]}"; do
+        echo -e " * $CHECK FAILED"
+    done
+    echo -ne "\e[0m"
+else
+    echo -e "\e[32mAll checks PASSED\e[0m"
+fi
+if [ "$ERR" ]; then
+    exit 1
+fi
+exit 0