Create Hooks for Warnings NG

[fcojfernandez]

PR to make Warnings NG Plugin executable on PCT:

• BeforeCheckoutHook since the plugin is multimodule
  • The Hook expects the same folder structure as in the repository
  • The plugin directory is the plugin folder
  • Hook allows the localcheckoutDir option
• BeforeExecutionHook since the plugin includes integration tests
  • New parent class for other plugins to be used
  • Hook for the Warnings NG Plugin itself

@bmunozm @raul-arabaolaza @imonteroperez

CC @uhafner fyi as maintainer of the Warnings NG Plugin

[raul-arabaolaza]

@fcojfernandez Code LGTM, and build failure looks like a infra issue, closing and reopening to trigger build again

[fcojfernandez]

The CI is not re-launched. Closing again ...