New issue by Anachron on void-packages repository

https://github.com/void-linux/void-packages/issues/13377
Description: ### System

* xuname:  
`Void 4.19.53_1 x86_64 GenuineIntel uptodate rFF`
* package:  
`postgresql-9.6.14_1`

### Expected behavior
- Install `postgresql`
- Link service
- Profit

### Actual behavior
- Service does not start, manually running it gives:
```
LOG:  skipping missing configuration file "/var/lib/postgresql/data/postgresql.auto.conf"
FATAL:  "/var/lib/postgresql/data" is not a valid data directory
DETAIL:  File "/var/lib/postgresql/data/PG_VERSION" is missing.
```

### Steps to reproduce the behavior
See `Expected behavior`.

### Reason
Postgresql requires one to run `initdb`. The default installation should run this automatically after install or give a warning in `INSTALL.msg`.