Create docs on the site for bashdocs

ShDoc doesn't provide a way to prepend with the structure Jekyll needs to create docs, so I wrote this shell function:

vvv_process_jekyll_shelldoc() {
    MDFILE="${1}"
    echo -e "---\ncategory: 10. Function Reference\ntitle: ${DOCFILE}\ndescription: Shellscript documentation for ${DOCFILE}\n---\n\n$(shdoc < $DOCFILE)" > $MDFILE
}

It prepends a header structure with the category etc, and takes the shell file to process as a parameter, e.g. vvv_process_jekyll_shelldoc provision/provision-site.sh, resulting in a doc ready for the .org site. It does need some adjustments though:

we need a loop that searches for files ending in .sh in the provision folder then calls this function
we need it to put the files in a target folder rather than alongside the original
we need to adjust Travis to clone VVV itself so it can run the process
we need to escape the slash in the filename so we don't cause issues with subfolders

Varying-Vagrant-Vagrants / VVV

Create docs on the site for bashdocs #2320