Update requirements & defaults

[nervo]

• [x] Update vagrant box supported versions (2.0.8|3.0.14|4.0.3)
• [x] Update default box version (3.0.0 -> 4.0.3)
• [x] Update vagrant box version for php < 7 (2.0.0 -> 2.0.8)
• [x] Update vagrant requirement version (1.8.4 -> 2.2.1)
• [x] Update vagrant landrush plugin requirement version (1.0.0 -> 1.3.0)
• [x] Update ansible requirement version (2.1.1 -> 2.6.5)
• [x] Update virtualbox requirement version (5.0.20 -> 5.2.22)
• [x] Update mysql default version (5.6 -> 57)
• [x] Update mariadb default version (10.1 -> 10.3)
• [x] Update elasticsearch default version (5 -> 6)

Fix #134 Fix #137 Fix #154

[ogizanagi]

But a lot of tests are failing now, as expectations updates are missing from the PR :)

[ogizanagi]

Thanks @nervo.