VIM-92: Fix Vim keymap to work better in Mac OS

- remove all static overrides from vim.xml
- introduce conflicts resolving
VIM-92: Fix Vim keymap to work better in Mac OS

- tests for keymap generation
VIM-92: Fix Vim keymap to work better in Mac OS

- ability to define extra shortcuts
VIM-92: Fix Vim keymap to work better in Mac OS

- add extra shortcuts for Linux keymaps
VIM-92 Alternative shortcuts for actions with shortcuts bound to IdeaVim

Alternative action shortcuts are obtained from standard shortcuts by
adding Alt+, Ctrl+, Shift+, Meta+, Alt+Ctrl+, etc. to them.
Merge branch 'vim-92'