fix(audio): update sortable markup after load to apply custom height

Update sortable markup after DOMContentLoaded to apply custom
audio element height. Only do it once on load.

This fixes #29.
feat(audio): show size on audio hover, hide on mouse out

- fetch and show audio size on the whole audio element hover,
not just download button
- change translations accordingly
- hide size on mouse out
- style size element similar to the audio length

This fixes #28.