More/custom sorting options

[markusfinell]

There is currently a setting to change in which order posts should be displayed, ascending or descending by date. We should add support for sorting by title and menu_order by default.

We should also enable custom sorting options by post meta. This could be defined in the config:

$config[] = [
  ...
  'order_by' => [
    'post_title', 
    '_event_date', 
    ...
  ]
] 

[perarnborg]

Would be good to enable aliasing of meta fields.

meta_key => [
  _event_date => 'Evenemangsdatum'
]

[perarnborg]

Also handle different types of fields, so we can sort as date, string, numeric.

Maybe as a setting (so you select "Sort as" when you pick a field) to avoid an overly complex configuration.

[perarnborg]

This was solved in #58