Add pagination for the list endpoint

[tcezard]

The list endpoint will potentially returns hundred of thousand of entries.
To make it manageable the content should be paginated.
The pagination will use page_token and page_size as query parameter and returns

{
	"total_size": total_size,
	"page_size": page_size,
	"page_token": page_token,
	"next_page_token": page_token + page_size, 
	"items": ["lsuhfdow7dhsoshxhddjsiqpz", "2pqrt62xf0a72ffkbshw27sk", ...]
}