feat: line specific rule toggling

Like other linters, ember-template-lint should allow users to enable and disable rules per line:

{{! template-lint-enable-line bare-strings }}

{{! template-lint-disable-line bare-strings }}

{{! template-lint-enable-next-line bare-strings }}

{{! template-lint-disable-next-line bare-strings }}

[rwjblue]

It is documented in this section of the README though maybe we need to make it even clearer. Would definitely like help.

---

An instruction will apply to all later siblings and their descendants:

<!-- disable for <p> and <span> and their contents, but not for <div> or <hr> -->
<div>
  <hr>
  {{! template-lint-disable }}
  <p>
    <span>Hello!</span>
  </p>
</div>

An in-element instruction will apply to only that element:

<!-- enable for <p>, but not for <div>, <hr> or <span> -->
<div>
  <hr>
  <p {{! template-lint-enable }}>
    <span>Hello!</span>
  </p>
</div>

An in-element instruction with the -tree suffix will apply to that element and all its descendants:

<!-- configure for <p>, <span> and their contents, but not for <div> or <hr> -->
<div>
  <hr>
  <p {{! template-lint-configure-tree block-indentation "tab" }}>
    <span>Hello!</span>
  </p>
</div>

[bertdeblock]

@rafaelbnp Should be here => https://github.com/ember-template-lint/ember-template-lint/blob/master/docs/configuration.md#per-template-file.