refactor: centralize pagination logic (#1227)

* refactor: centralize pagination logic into a new helper partial used for page titles and index display

* fix: list.html does not exclude hidden pages

* refactor: Simplify title generation logic

layouts/partials/helper/paginator.html

@@ -0,0 +1,23 @@
+{{- $pages := "" -}}
+
+{{- if .IsHome -}}
+    {{ $pages = where .Site.RegularPages "Section" "in" .Site.Params.mainSections }}
+    {{ $pages = where $pages "Params.hidden" "!=" true }}
+{{- else if eq .Kind "term" -}}
+    {{ $pages = where .Pages "Params.hidden" "!=" true }}
+{{- else if or (eq .Kind "section") (eq .Kind "taxonomy") -}}
+    {{ $subsections := .Sections }}
+    {{ $pages = .Pages | complement $subsections }}
+    {{ $pages = where $pages "Params.hidden" "!=" true }}
+
+    {{- if eq (len $pages) 0 -}}
+        {{/* See complete logic in list.html */}}
+        {{- $pages = $subsections -}}
+    {{- end -}}
+{{- end -}}
+
+{{- if $pages -}}
+    {{ $pages = .Paginate $pages }}
+{{- end -}}
+
+{{ return $pages }}