Fix issue 229 - New-JiraIssue should take params from pipeline.

Description

The here was due to how PowerShell handles input via the pipeline, see an in depth explanation with examples here: https://learn-powershell.net/2013/05/07/tips-on-implementing-pipeline-support/. The function will be unable to use $Profile in the begin block, so i moved that code into the Process block. This is necessary so that multiple new issues can be passed in and processed one after the other.

Motivation and Context

This resolves https://github.com/AtlassianPS/JiraPS/issues/229 and allows a user to fill an excel sheet or other object with new issues and pipe them into new issue. closes #229

Types of changes

[x] Bug fix (non-breaking change which fixes an issue)
[x] 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] I have added Pester Tests that describe what my changes should do.
[x] I have updated the documentation accordingly.

AtlassianPS / JiraPS