move lessons out of web site

will move select lessons back to "educators" section

docs/lessons/counter/challenges.md

@@ -1,37 +0,0 @@
-# counter challenges
-
-Coding challenges for the counter.
-
-## Before we get started
-
-Complete the following [guided tutorial](/lessons/counter/activity) At the end of the tutorial, click **keep editing**. Your code should look like this:
-
-```blocks
-let count = 0
-input.onButtonPressed(Button.A, () => {
-    count = count + 1
-    basic.showNumber(count)
-})
-```
-
-### Challenge 1
-
-Let's add the code to `count` when `B` is pressed. Add an event handler with `on button pressed(B)` then add the code to `count`.
-
-
-```blocks
-let count = 0
-input.onButtonPressed(Button.A, () => {
-    count = count + 1
-    basic.showNumber(count)
-})
-input.onButtonPressed(Button.B, () => {
-    count = count - 1
-    basic.showNumber(count)
-})
-```
-
-### Challenge 3
-
-Now let's try to reset the counter when the micro:bit is shaken. You will need to register an event handler with `on shake`.
-