Fix prev/next links on public profile page (#6497)

* Fix prev/next links on public profile page

* Don't make pagination urls if no available statuses

* Fix empty check method

* Put left chevron before prev page link

* Add scope for pagination "starting at" a given id

* Status pagination try 2:

s/prev/older and s/next/newer
"older" on left, "newer" on right
Use new scope for "newer" link
Extract magic 20 page size to constant
Remove max_id from feed pagination as it's not respected

* Reinstate max_id for accounts atom stream

* normalize

config/locales/en.yml

@@ -545,7 +545,9 @@ en:
           trillion: T
           unit: ''
   pagination:
+    newer: Newer
     next: Next
+    older: Older
     prev: Prev
     truncate: "…"
   preferences: