Added Module parameter and an [IO.Path]::Combine() to Build-PSBuildUpdatableHelp

[IMJLA]

Description

The Module parameter removes the dependency on the $ModuleName variable in the parent scope while maintaining the existing behavior of inheriting its value.

The LandingPagePath key in $cabParams now uses the [IO.Path]::Combine([string[]]) method rather than manual string concatenation

Related Issue

https://github.com/psake/PowerShellBuild/issues/54

Motivation and Context

This will make it easier to use Build-PSBuildUpdatableHelp in custom psake files or other contexts

How Has This Been Tested?

All 195 existing Pester tests passed

Also tested in a vacuum as demonstrated by the example in the Issue

Screenshots (if appropriate):

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [x] My code follows the code style of this project.
• [x] My change requires a change to the documentation.
• [x] I have updated the documentation accordingly. (I think? Should I do anything other than the comment-based help?)
• [x] I have read the CONTRIBUTING document.
• [ ] I have added tests to cover my changes. (Sorry, I don't know where to do this, don't see existing per-function tests, I am a testing n00b)
• [x] All new and existing tests passed.