Filter secrets from log files

[sayedihashimi]

Now that we have add the ability to filter the secrets from the PS console we should look into filtering secrets in the msbuild log files that are written. We can use the FileReplacer PowerShell module that is used in the build script https://github.com/ligershark/psbuild/blob/master/build.ps1#L139.

When we implement this we should:

• Add a global flag to disable this
• Add a parameter to Invoke-MSBuild to disable for that build
• Measure the perf when building projects that create large files

After doing this we can automatically upload log files to AppVeyor as artifacts as mentioned in #255