Create new FlagSets to create new subcommands.
- The version subcommand prints the version and build info.
- The generate subcommand generates the CV PDF documentation.
Allow users to limit the amount of employment history shown in the PDF
document by specifying a time range. This is a breaking change as the
structure of the CV needs to slightly change. The employment's start and
end dates need to be represented as integers.
Additional refactoring:
- The CV type is now in the internal cv package.
- The template functions are now in the internal templateFuncs package.