Some updates to Resultset table component

[GomezIvann]

Checklist
(Check off all the items before submitting)

• Build process is done without errors and all tests pass in the /lib directory.
• Self-reviewed the code before submitting.
• Meets accessibility standards.
• Added/updated documentation to /website as needed.
• Added/updated tests as needed.

Description
Some improvements to the Resultset Table:

• The Table now extends its width to the maximum available (100%), just like our regular Table, regardless of its container display.
• The gap between the sorting icons and a header title is now 8px, as it stands in the documentation. Until now, that wasn't happening.
• Removing unnecessary styles from the component and useless containers, the component now is more simple.
• New visual tests.
• Minor code refactors and new accessibility features (aria-sort and roles were included).

Screenshots

Code:

    <ExampleContainer>
      <Title title="Flex" theme="light" level={4} />
      <DxcFlex>
        <DxcResultsetTable columns={columnsSortable} rows={rowsSortable} />
      </DxcFlex>
    </ExampleContainer>

Closes #1425