Incorporate the collapsible code block

[snejus]

Something I use in the docs often is the <details><summary> html block which allows to embed code blocks of any size without losing out on the readibility - you can open and close the thing as you like.

Now the problem is that Confluence doesn't parse it (or does it in a weird way - I don't remember) and instead they have their own collapsible something, which is enabled through a flag in the code macro. This PR enables it, as well as the title field.

It's a bit of funky way to do it, but luckily github's markdown/codeblock parser is flexible enough to allow this:

```python collapse title Hello this is a Beautiful codeblock

def func():
    print("Beautiful")

# ... and 200 more lines of funk
```

And on confluence it looks this way:

Best part is that github's version looks as usual, seems like they just ignore the extra words.

If we wrap it in

<details>
<summary>Hello this is a Beautiful codeblock</summary>

```python collapse title Hello this is a Beautiful codeblock

def func():
    print("Beautiful")

# ... and 200 more lines of funk
```
</details>

We get

Hello this is a Beautiful codeblock

def func():
    print("Beautiful")

# ... and 200 more lines of funk

The lines that contain these tags have to be removed before uploading to confluence but that's specific to how I use it so may not apply to everyone - otherwise piping the file through sed /<\/\?details>\|<\/\?summary>/d removes them.

Let me know if I should remove the printfs from the template - it's a rather subjective change so I'm happy to let them go if you have doubts about them.

[kovetskiy]

Thank you!