function to paste header template

[aghaynes]

Is your feature request related to a problem? Please describe.
A function that will paste a template header into an R file

Describe the solution you'd like
CTUtemplate::paste_head() results in a header being inserted into a file open in RStudio

Describe alternatives you've considered
copy/paste from other files

Additional context
implementation probably via rstudioapi::insertText(output)
could have an option to print a full header (with export date etc)