Add white & black lists for var-naming

This PR introduces a white & black lists of initialisms for the
`var-naming` rule.

Now the rule can be configured with:

```toml
[rule.var-naming]
  arguments = [["ID"], ["VM", "BAR"]]
```

This way, the linter will ignore `customId` but will throw on `customVm` or `customBar`.

Fix #41

test/utils.go

@@ -275,7 +275,7 @@ func TestLintName(t *testing.T) {
 		{"IEEE802_16Bit", "IEEE802_16Bit"},
 	}
 	for _, test := range tests {
-		got := lint.Name(test.name)
+		got := lint.Name(test.name, nil, nil)
 		if got != test.want {
 			t.Errorf("lintName(%q) = %q, want %q", test.name, got, test.want)
 		}