Create a new 'Deployment' manual section, move stuff around

I was pretty sure that this section existed, and then realised that not ...

At the moment, there is nothing new there. Feel free to mention any theme that should be described there.

- Docker ?
- AWS / Azure / ... ?
- Heroku ?
- Apache vs. nginx ? Common pitfalls ?

Please be creative !
/Buildbot uses the sqlite3 database backend by default./