Add HTML scan to retrieve variable operations

[sdibernardo]

As of now, HTML variable access of any kind is not part of the process variable retrieval process. At least the basic usage of embedded forms (if in the classpath) should be scanned to find variables and the respective operations.

Example HTML for embedded form:

<form class="form-horizontal">
    <div class="form-group">
        <div>
            <label class="control-label col-md-4">This is a label</label>
            <textarea class="margin-top" readonly cam-variable-name="content"></textarea>
        </div>
        <div>
            <label class="control-label col-md-4">Approved:</label>
            <div class="display">
                <input type="checkbox"
                       cam-variable-name="approved"
                       cam-variable-type="Boolean"
                       required
                       class="form-control"/>
            </div>
        </div>
    </div>
</form>