[ticket/13225] Use passwords manager instead of phpbb_hash in migration

PHPBB3-13225
[ticket/13225] Prefix converted passwords with $CP$ in phpBB 3.0.5-RC1

PHPBB3-13225
[ticket/13231] Update the dependencies of the migration contact_admin_form

PHPBB3-13231
[ticket/13227] Properly handle curlwrapper headers in remote avatars

Read a bit of the file to ensure header values are populated and then
handle headers in the nested array structure too.

PHPBB3-13227
Merge pull request #3083 from Nicofuma/ticket/13231

[ticket/13231] Update the dependencies of the migration contact_admin_form
Merge pull request #3085 from naderman/ticket/13227

[ticket/13227] Properly handle curlwrapper headers in remote avatars