It is impossible to ignore `evil-collection` anymore. `evil-magit` has been
deprecated recently and moved to `evil-collection`.
It will save time and effort for both Spacemacs and Evil to share and contribute
to `evil-collection` imo.
However I strongly prefer Spacemacs binding scheme over evil-collection's one.
We should only pick what we need from `evil-collection`.
This PR add mechanism to embrace `evil-collection` and apply it to shell layer (`vterm`)
and git layer.
Delete layer evil-cleverparens and move the package to spacemacs-evil layer.
The feature is called "Safe structurral editing" for lisp dialects. Support for
it is added via pre-init functions in each of the concerned layer and proper
documentation is added to their README.org files.
This also removes the recently added package evil-smartparens. The goal is
to choose the best package for evil safe structural editing. For now we use
evil-cleverparens as we supported it first, if evil-smartparens is shown to be
a better package we will be able to switch to it.
