Add LTS changelog

[Ginden]

Is your feature request related to a problem? Please describe.
I, as developer, want to upgrade Node.js in my project or library from older LTS version to newer one.

Describe the solution you'd like
I would like to read single documentation page, listing all revelant changes made between old LTS and new LTS.

Eg. if I want to upgrade from Node 8 to Node 10 I have to read whole changelog for V9 and V10, including hundreds of docs and test fixes.

Therefore, I would like to see page "upgrading from Node 8 to Node 10", with list of "notable" changes made in Node 9 and pre-LTS Node 10 (and filtered commit list).

[Trott]

@Ginden Does https://nodejs.org/en/blog/uncategorized/10-lts-to-12-lts/ fill the need here? Or is that not sufficient?

[Ginden]

It's pretty good.