Ansible, Scala key bindings for Ensime, Support for niche languages, Lisp state everywhere, tweaks and fixes

• New contrib layer ansible (thanks to BrianHicks)
• New contrib layer extra-langs which installs a bunch of niche languages (thanks to trishume)
• trishume user layer is now deprecated
• Lots of new key bindings for scala layer using ensime, see documentation for more info (thanks to bjarkevad)
• Add hungry-delete with a toggle on SPC t d, default value is nil (thanks to trishume)
• Add the possibility to use evil-lisp-state everywhere, it is now on SPC k prefix. Some key bindings have been modified to get better mnemonic keys, see documentation for more info
• Initialize ruby-test-mode in the ruby layer (thanks to kofno)
• New variable dotspacemacs-loading-progress-bar with default value t. On some systems or builds turning this setting off (nil) can improve the startup performance
• Support GOPATH with multiple entries in go layer (thanks to artemave)
• Put back git gutter on the right fringe by default (on the left fringe it can be overwritten by flycheck icons)
• New functions to clear python inferior buffer on C-l (thanks to danielwuz)
• Update all SPC m i bindings for launching an inferior REPL process to the new convention SPC m s i
• Refactor spacemacs init to make it possible for a user to override some evil parameters which must be set before requiring evil. For instance the parameters evil-want-C-u-scroll and evil-want-fine-undo
• Update the conventions
• Typo and various fixes (thanks to luxbock, mijoharas, nwolfe, devinrhode2 and hrvladev)