Reading parameters from $BuildInfo (i.e. the Build.yaml file)

### Problem description

suggestion to create an alternative to the use envrionment variables such as $Env:HelpSourceFolder inside the Config if not set via param input, and using a default as last resort.

### Verbose logs

```text
n.a.
```

### How to reproduce

n.a.

### Expected behavior

n.a.

### Current behavior

n.a.

### Suggested solution

have Vars section in the build.yaml as alternative to env vars

e.g.

```yml
Vars:
HelpSourceFolder: docs/subfolder
```

### Operating system the target node is running

```text
OsName : Microsoft Windows 11 Pro
OsOperatingSystemSKU : 48
OsArchitecture : 64-Bit
WindowsVersion : 2009
WindowsBuildLabEx : 22000.1.amd64fre.co_release.210604-1628
OsLanguage : de-DE
OsMuiLanguages : {de-DE, en-US}
```

### PowerShell version and build the target node is running

```text
Name Value
---- -----
PSVersion 5.1.22000.282
PSEdition Desktop
PSCompatibleVersions {1.0, 2.0, 3.0, 4.0...}
BuildVersion 10.0.22000.282
CLRVersion 4.0.30319.42000
WSManStackVersion 3.0
PSRemotingProtocolVersion 2.3
SerializationVersion 1.1.0.1
```

### Module version used

```text
Name Version Path
---- ------- ----
Sampler 0.112.0 C:\Users\fheiland\Documents\PowerShell\Modules\Sampler\0.112.0\Sampler.psd1
```