[ticket/12562] Add max-width to proSilver

PHPBB3-12562
[ticket/12612] Prefix show_profile() with phpbb and delete unused global

PHPBB3-12612
[ticket/12612] Prefix _sort_last_active() with phpbb_

PHPBB3-12612
[ticket/12612] Prefix custom UCP module function with phpbb_

PHPBB3-12612
[ticket/12612] Prefix handle_post_delete() with phpbb and remove unused global

PHPBB3-12612
[ticket/12612] Prefix upload_popup() with phpbb_

PHPBB3-12612
[ticket/12612] Prefix module url functions with phpbb_

PHPBB3-12612
[ticket/12612] Prefix get_*_data() with phpbb_ and delete unused global

PHPBB3-12612
[ticket/12612] Prefix mcp_sorting() with phpbb_

PHPBB3-12612
[ticket/12612] Prefix check_ids() with phpbb_

PHPBB3-12612
[ticket/12648] Improve UCP/MCP/Posting tabs

PHPBB3-12648
[ticket/12648] IE8 & IE9 color fix

PHPBB3-12648
[ticket/12648] More style fixes and also cleaned up CP left navigation

PHPBB3-12648
[ticket/12648] Fix and modernize ACP header tabs

PHPBB3-12648
[ticket/12648] Added ARIA functionality

PHPBB3-12648
[ticket/12648] Fix poll tab display error

PHPBB3-12648
[ticket/12648] Fix poll tab and revert unrelated color change

PHPBB3-12648
[ticket/12648] Slightly clear ACP active tab border

PHPBB3-12648
[ticket/12648] RTL fix & ACP border fix

PHPBB3-12648
Merge remote-tracking branch 'PayBas/ticket/12648' into develop-ascraeus

* PayBas/ticket/12648:
  [ticket/12648] RTL fix & ACP border fix
  [ticket/12648] Slightly clear ACP active tab border
  [ticket/12648] Fix poll tab and revert unrelated color change
  [ticket/12648] Fix poll tab display error
  [ticket/12648] Added ARIA functionality
  [ticket/12648] Fix and modernize ACP header tabs
  [ticket/12648] More style fixes and also cleaned up CP left navigation
  [ticket/12648] IE8 & IE9 color fix
  [ticket/12648] Improve UCP/MCP/Posting tabs