Support wildcards for the tasks file-delete or file-copy

[Seddryck]

It would be great to support wildcards into these two tasks (copy and delete).

The following command will delete all the files for which the filename is starting by CRDS_FTP_FTP_ and having an extension .csv.

<cleanup>
   <file-delete-pattern path="U:\Data Quality Checks\" pattern="CRDS_FTP_FTP_*.csv"/>
</cleanup>

The following command will delete all the files with an extension .csv or an extension .txt

<cleanup>
   <file-delete-extension path="U:\Data Quality Checks\" extension=".csv;.txt"/>
</cleanup>

Comparable methods are supported to copy files: file-copy-pattern and file-copy-extension.

[Seddryck]

An alpha version is available at https://ci.appveyor.com/project/Seddryck/nbi/builds/24907589/artifacts
1.21.0-alpha.1+45

[Seddryck]

Beta available at https://ci.appveyor.com/project/Seddryck/nbi/builds/24917349/artifacts or upgrade package via Update-Package NBi.Framework -version 1.21.0-beta0047.

Documentation updated.