[ticket/12176] Add functional test for founder deletion message.

PHPBB3-12176
[ticket/12176] Display correct message when trying to delete founder.

PHPBB3-12176
[ticket/12160] Add function to check if phpBB is installed.

PHPBB3-12160
[ticket/12160] Check if phpBB is installed before creating phpBB container.

PHPBB3-12160
[ticket/9871] Update version check file to use json format

PHPBB3-9871
[ticket/12160] Move phpbb_check_installation_exists() to functions_install.php

PHPBB3-12160
[ticket/12160] Use phpbb_check_installation_exists() in the other modules.

PHPBB3-12160
[ticket/9725] Create an Azure SQL compatible Schema

Two problems were encountered when installing on AzureSQL:
-Azure SQL does not support the ON clause of T-SQL
-Azure SQL requries a clustered index AKA primary key on all tables

The fix is makeshift; it introduces questionable primary indices, which should be replaced with auto--increment columns.

PHPBB3-9725
[ticket/9725] Add dummy indexes for Azure

SQL Azure requires a primary AKA clustered key on every table.
This adds a dummy INT column to act as key,
avoiding possible duplicate entries.
so that these columns can support bigger (speak: huge) tables

PHPBB3-9725
[ticket/8785] Rebuilding posting_editor pm head + new language vars

PHPBB3-8785
[ticket/8785] Little spaces mistake

PHPBB3-8785
[ticket/8785] Scrollbar to Reciepients and BCC with max-height: 200px

PHPBB3-8785
[ticket/8785] Adds two <hr /> to seperate recipients and BCC

PHPBB3-8785
[ticket/9871] Use $request->variable instead of request_var

PHPBB3-9871
[ticket/9871] Restore get_remote_file

PHPBB3-9871
[ticket/9871] Restore phpbb_version_compare

PHPBB3-9871
[ticket/9871] Mark test as slow

PHPBB3-9871
[ticket/9871] Typehint and comment on var types

PHPBB3-9871
[ticket/9871] Fix tests

PHPBB3-9871
[ticket/8785] Adds a new optical improvement, new file and fixes html bugs

PHPBB3-8785