New-xDscResource: Change Resource Output File encoding to ASCII

[X-Guardian]

Pull Request (PR) description

This PR changes the resource output files produced by the New-xDscResource function to use ASCII encoding instead of Unicode to conform to the Dsc style guidelines.

This Pull Request (PR) fixes the following issues

• Fixes #49
• Fixes #35

Task list

• [x] Added an entry under the Unreleased section of the change log in the README.md. Entry should say what was changed, and how that affects users (if applicable).
• [ ] Documentation added/updated in README.md.
• [ ] Comment-based help added/updated for all new/changed functions.
• [ ] Localization strings added/updated in all localization files as appropriate.
• [x] Unit tests added/updated.
• [x] New/changed code adheres to DSC Resource Style Guidelines and Best Practices.

---

This change is 

[codecov-io]

Codecov Report

Merging #81 into dev will not change coverage. The diff coverage is 80%.

@@           Coverage Diff           @@
##              dev      #81   +/-   ##
=======================================
  Coverage   61.26%   61.26%           
=======================================
  Files           1        1           
  Lines         994      994           
  Branches        3        3           
=======================================
  Hits          609      609           
  Misses        382      382           
  Partials        3        3

Impacted Files	Coverage Δ
xDSCResourceDesigner.psm1	61.26% <80%> (ø)	:arrow_up:

---

Continue to review full report at Codecov.

Legend - Click here to learn more Δ = absolute <relative> (impact), ø = not affected, ? = missing data Powered by Codecov. Last update 492834e...49d088d. Read the comment docs.

[gaelcolas]

This one looks good code-wise, but I'd need to run different tests on different version of PowerShell to be sure it works fine. It should, but I vaguely remember some odd behaviours I want to avoid.