Rework header and footer commands

Currently, the heading is structured as follow:

% Header and footer (will be filled at publication)
% arguments are:
% {article-id}{article-link}{year}{pages}{date submitted}{date published}{author-full-names}{special-issue-title}{special-issue-editors}
% At submission, authors can optionally fill the year and author-full-names (any other information will not be displayed)
%
% Publications instructions for authors of FINAL ACCEPT papers, before uploading final proof to scholastica:
%  article-id: This is provided upon acceptance from the Associate Editor
%  article-link: This is provided upon acceptance from the Associate Editor
%  year: the submission year
%  pages: "1-X" where X is the number of pages in this final paper (including appendices)
%  date-submitted: Date submitted to MELBA: mm/yyyy
%  date-published: Today's date: mm/yyyy
%  author-full-names: Last names of all the authors, separated by commas or 'and' before final author.
%  special-issue-title: If part of a special issue, name of the issue *as given by the Associate Editor*. Otherwise, leave blank.
%  special-issue-editors: If part of a special issue, editors of the issue *as given by the Associate Editor*. Otherwise, leave blank.
\melbaheading{YYYY:NNN}{https://www.melba-journal.org/article/XX-AA}{YYYY}{1-?}{m1/yyyy}{m2/yyyy}{Dalca and Sabuncu}{}{}

This long list is (even to me) sometimes a big long to parse, and using it correctly in melba.sty is trickier than it should be. Splitting it into several, independent variable might help (while also helping to solve #1 ). For instance, we could do something along the lines of:

\melbaid{YYYY:NNN}
\melbalink{https://www.melba-journal.org/article/YYYY:NNN}  % Or simply remove that one
\melbayear{YYYY}
\datesubmitted{mm/yyyy}
\datepublished{mm/yyy}
\authorfullnames{Danca and Sabuncu}
\melbaspecialissue{Melba sample special issue}
\melbaspecialissueeditors{E. Ditor, W. Riter}

Pages numbering could be done automagically, with the package lastpage: 1-\pageref{\lastpage}} in place of 1-?

Adding a new option (accepted-special-issue) might also help to make sure that the special issue fields are not displayed by accident.

melba-journal / submission

Rework header and footer commands #4