removing _1 suffix

coming from #342,
this will change container naming to avoid the `_1` suffix, the change will be:
```
container_1 => container
container_2 => container_2
container_3 => container_3
...
```
I updated all docs I found to reflect this. test

Signed-off-by: Benjamin Eidelman <beneidel@gmail.com>
Likewise, the docs should just have 5432 hard-coded here. It's already part of the variable name, so using the variable achieves nothing other than increased complexity/maintenance costs. The only part that is truly variable is the IP of the linked container.