* fix: persist original file path when using bases
Prior to this change, the resulting lock file was called `<bases[0]>.lock`,
instead of `<filename>.lock`.
This change ensures the final, merged state has the correct `.FilePath`.
* test: Assert proper FilePath in layered HelmState
This adds `values` to state files as proposed in #640.
```yaml
values:
- key1: val1
- defaults.yaml
environments:
default:
- values:
- environments/default.yaml
production:
- values:
- environments/production.yaml
```
`{{ .Valuese.key1 }}` evaluates to `val1` if and only if it is not overrode via the production or the default env, or command-line args.
Resolves#640
Eric Bailey
KUOKA Yusuke