Allow setting default values

[phanect]

Something like following is expected.

{
  "editorconfig/charset": [ "error", { fallback: "always" }], // Or `fallback: "never"` or `fallback: "ignore"` (default)
  "editorconfig/no-trailing-spaces": [ "error", { fallback: "always" }], // Or `fallback: "never"` or `fallback: "ignore"` (default)
  "editorconfig/eol-last": [ "error", { fallback: "always" }], // Or `fallback: "never"` or `fallback: "ignore"` (default)
  "editorconfig/indent": [ "error", { fallback: "tab" }], // Or `fallback: 2` (any positive number allowed) or `fallback: "ignore"` (default)
  "editorconfig/linebreak-style": [ "error", { fallback: "unix" }], // Or `fallback: "windows"` or `fallback: "ignore"` (default)
}