Enhancement: Add the ability to sort by date field.

[iveptawebadmin]

Currently, you can sort by last modified, but my content doesn't have that field.
The file list shows the 'date' field that I do have in my content, but I can't sort files by it.

[estruyf]

This can be linked to #76 as I want to allow open sorting based on anything you define.

Currently, the last modified sorting is done based on the file stats itself, not from a metadata field in the file,

[estruyf]

Support for custom sorting will be added in 5.5.0. You can already test it out in the latest beta. For this, a new setting has been added. More information about it can be found here: https://beta.frontmatter.codes/docs/settings#frontmatter.content.sorting

"frontMatter.content.sorting": [
  {
    "title": "Date (asc)",
    "name": "date",
    "order": "asc",
    "type": "date"
  },
  {
    "title": "Date (desc)",
    "name": "date",
    "order": "desc",
    "type": "date"
  }
]

[bwklein]

It works as expected in beta. One preference I would have is to find a way to preserve the last chosen sort method, so that when you go back to the Dashboard, the same sort as last time is applied.

[estruyf]

Again, a great suggestion!

[estruyf]

@bwklein sorting state is now kept. So when opening the dashboard again, it will use the last used selection.