[ticket/12857] Add template events breadcrumbs_before/after

PHPBB3-12857
[ticket/12857] Add missing template events breadcrumb_prepend

To insert links after site-home

PHPBB3-12857
[ticket/12851] Fix the Font colour button title

PHPBB3-12851
Merge pull request #2733 from n-aleha/ticket/12851

[ticket/12851] Fix the Font colour button title

* n-aleha/ticket/12851:
  [ticket/12851] Fix the Font colour button title
[ticket/12887] Fix Typo: offest -> offset

PHPBB3-12887
[ticket/12857] Clarify events.md on difference between PS and SS2 breadcrumbs

PHPBB3-12857
[ticket/12857] Add header/footer distinction for subsilver2 events

PHPBB3-12857
Merge remote-tracking branch 'paybas/ticket/12857' into develop-ascraeus
Merge pull request #2773 from bantu/ticket/12887

[ticket/12887] Fix Typo: offest -> offset