Add static help text to CiviHR UIs

Ask Andrew to walk through the various screens and prepare a spreadsheet with help text. The spreadsheet would include columns for "Screen Name", "Field Name", "Help Text".

TODO: There's an interesting decision about how to handle help text for custom-data based extensions (hrqual, hrcareer, hrvisa, etc). We could use the CustomField help.
Pro: Zing likes the idea of admin-managed help text, and we almost get that for free on hrqual/hrcareer. (We would need to rework the handling of CustomGroup.is_reserved=1.)
Con: In the typical case where a site-admin hasn't customized help-text, it's harder for developers to issue updates/corrections to the help-text.
Con: This doesn't work with "Job", "Contact", or any other entity based on GenCode.

Strategically, I think it's better to allow extensions to declare the help text for CustomFields in PHP/TPL/XML (so that they never need a DB upgrade for help text), but there could be some brief tactical advantage in using CustomField.