External library added in libs folder should be referred in windows

[NivedhaSenthil]

Expected behavior

External libraries added in libs folder should be referred when specified in properties file as below gauge_additional_libs = libs/*

Actual behavior

Libraries are not referred and throws package does not exists error.

Linked https://github.com/getgauge/gauge-java/issues/377#issuecomment-616606623 ,

Gauge version

Gauge version: 1.0.8
Commit Hash: 28617ea

Plugins
-------
html-report (4.0.10)
java (0.7.6)
screenshot (0.0.1)

[taplar]

Related to https://github.com/getgauge/gauge-java/pull/419#discussion_r413974030

While the resolution of the gauge_additional_libs should be addressed, should there be a consideration made for a pre-defined directory in a project that would always be included on the classpath to potentially reduce its size? Currently, this type of logic is being done in the launcher.ps1 > AddRunnerInClassPath to include all libs in the $PluginDir. Should there also potentially be a $env:GAUGE_PROJECT_ROOT/<some directory>/* also added as a generic default?