LPS-52109 - Copy 'StringPool' into the poshi-runner module
LPS-52109 - Change the 'StringPool' package name to 'com.liferay.poshi.runner.util'
LPS-52109 - Copy 'Validator' to the 'poshi-runner' module
LPS-52109 - Copy 'CharPool' to the 'poshi-runner' module
LPS-52109 - Remove unneeded functionality from 'CharPool'/'Validator'