Lemmy schedule now supports counters

Along with a few fixes that hopefully make docker work again, I've added two new features:

• when you paste a link into the URL field, the title of the page will be fetched and filled into the Title field (if the Title field is empty)
• you can now use counters in your titles

Counters are basically named variables that increase after each successful post, those are mostly useful for recurring post. They can start at any value and by incremented by any value (well, except zero). They can be injected using the same syntax as dates:

• #[Counter('counter-name')]#

Just a reminder that you can use #[InjectDate('Y-m-d')]# syntax to insert the date at the time of posting (of course replace Y-m-d with your desired format)