Extend zowe plugins verbs to show information for a plugin's first steps

[Joe-Winchester]

Problem: After installing a plugin there may be first steps required by a user to configure back end systems and perform steps to enable the plugin to function.

Solution:. Have a common verb zowe plugins gettingstarted <plugin-name> or zowe plugins firststeps <plugin-name>. This could be done on a plugin by plugin, e.g,. zowe plugin-name info but then another plugin may be different such as zowe plugin-name readmefirst and the request is to have a common way for plugins to describe this in the imperative base command. This could be implemented with a firststeps , for example in the imperative.ts there could be a firststeps section.

This request has come from a number of vendor extensions who want to separate help text that is common to the first steps to the help text that is needed for operating the CLI, and to do this in a way that has common verbage syntax between extensions.