Add filters to the admin panel

[DavidVanDeursen]

Closes #48

[stickyPiston]

It looks good, nice work! As a general remark, it would be nice if you could add a few comments here and there explaining what each function does, since the names are not always too clear. Also sorry for the late review! ^_^

[stickyPiston]

I'm not a fan of hardcoding the filter types like that, so i propose to make a list of filter names to look for, and if it is found then add it the filters object. Something along the lines of the following:

const filterNames = ["category", "status", "name"];
function getFilters(filterString) {
  const strings = filterString.split(" ");
  const filters = {};
  const searchTerms = [];

  for (const string of strings) {
    const [type, value] = string.toLowerCase().split(":");
    if (value && filterNames.includes(type)) {
      filters[type] = value;
    } else {
      searchTerms.push(string.trim());
    }
  }

  return [searchTerm.join(" "), filters];
}