Clean-up the verbiage in the new-user plugin setup dialog

I worked much of this out with @orrc and @omehegan in #jenkins-community, but
feel these string changes will make the dialog more clear and understandable to
a new Jenkins user.

[FIX JENKINS-33464]

core/src/main/resources/jenkins/install/pluginSetupWizard.properties

 installWizard_welcomePanel_title=Getting Started
-installWizard_welcomePanel_banner=Initial Jenkins Setup
-installWizard_welcomePanel_message=Choose plugins. This will add features to your Jenkins environment.
-installWizard_welcomePanel_recommendedActionTitle=Start with recommended plugins
-installWizard_welcomePanel_recommendedActionDetails=Install the set of plugins the community finds most useful
-installWizard_welcomePanel_customizeActionTitle=Customize your plugins
-installWizard_welcomePanel_customizeActionDetails=Select from a community approved list of plugins
+installWizard_welcomePanel_banner=Customize Jenkins
+installWizard_welcomePanel_message=Plugins extend Jenkins with additional features to support many different needs.
+installWizard_welcomePanel_recommendedActionTitle=Install suggested plugins
+installWizard_welcomePanel_recommendedActionDetails=Install plugins the Jenkins community finds most useful.
+installWizard_welcomePanel_customizeActionTitle=Select plugins to install
+installWizard_welcomePanel_customizeActionDetails=Select and install plugins most suitable for your needs.
 installWizard_offline_title=Offline
 installWizard_offline_message=This Jenkins instance appears to be offline. \
 <p style="font-size:18px; margin-top: 6%"> \
@@ -29,13 +29,13 @@ installWizard_installing_detailsLink=Details...
 installWizard_installComplete_title=Installed
 installWizard_installComplete_banner=Jenkins is ready!
 installWizard_pluginsInstalled_message=Your plugin installations are complete.
-installWizard_installComplete_message=Your Jenkins installation is complete.
-installWizard_installComplete_finishButtonLabel=Get Started
+installWizard_installComplete_message=Your Jenkins setup is complete.
+installWizard_installComplete_finishButtonLabel=Start using Jenkins
 installWizard_installComplete_restartRequiredMessage=Some plugins require Jenkins to be restarted.
 installWizard_installComplete_restartLabel=Restart
 installWizard_installIncomplete_title=Resume Installation
 installWizard_installIncomplete_banner=Resume Installation
-installWizard_installIncomplete_message=Jenknins was restarted during installation and some plugins didn't seem to get installed.
+installWizard_installIncomplete_message=Jenkins was restarted during installation and some plugins didn't seem to get installed.
 installWizard_installIncomplete_resumeInstallationButtonLabel=Resume
 installWizard_saveFirstUser=Save and Finish
 installWizard_skipFirstUser=Skip