Improve accessibility for question display

[mchurchward]

Created the https://github.com/PoetOS/moodle-mod_questionnaire/tree/accessibilityimprovements branch to work on this.

[mchurchward]

Checkbox should use a structure like:
<fieldset class="c-group">
<legend>What's your favorite meal?</legend>

<div class="c-group__item">
    <input id="m1" type="checkbox">
	<label for="m1">Meal 1</label>
</div>

<div class="c-group__item">
    <input id="m2" type="checkbox">
	<label for="m2">Meal 2</label>
</div>

<div class="c-group__item">
	<input id="m3" type="checkbox">
	<label for="m3">Meal 3</label>
</div>

</fieldset>

[mchurchward]

Checkbox question is currently rendered as:

<fieldset id="qn-1054" class="qn-container">
    
    <legend class="accesshide">Question #1</legend>
    <div class="qn-legend">
        <div class="qn-info">
            <h2 class="qn-number">1</h2>
        </div>
        
    </div>
    <div class="qn-content">
        <div class="qn-question ">
            <label for="q1054">
            <div class="no-overflow"><p>Check all that apply</p></div>
            </label>
        </div>
        <div class="qn-answer">
            <!-- Begin HTML generated from question_check template. -->
<input id="checkbox_1170" value="1170" name="q1054[1170]" type="checkbox">
<label for="checkbox_1170">Mom</label>

<br>
<input id="checkbox_1171" value="1171" name="q1054[1171]" type="checkbox">
<label for="checkbox_1171">Dad</label>

<br>
<input id="checkbox_1172" value="1172" name="q1054[1172]" type="checkbox">
<label for="checkbox_1172">Son</label>

<br>
<input id="checkbox_1173" value="1173" name="q1054[1173]" type="checkbox">
<label for="checkbox_1173">Daughter</label>

<br>
<input id="checkbox_1191" value="1191" name="q1054[1191]" type="checkbox">
<label for="checkbox_1191">Other kinship</label>
<input size="25" name="q1054[o1191]" onclick="other_check(name)" value="" type="text">
<br>
<!-- End HTML generated from question_check template. -->
        </div>
    </div>
</fieldset>

[mchurchward]

Ick. I think each question type needs to define its own container so that fieldsets and legends are only used where they should be.