Use original consensus client images

[stefa2k]

Right now we make use of stereum built docker images, like stereum/nimbus and stereum/lighthouse. Please replace these with the original consensus client images.

• Replace stereum/lighthouse docker image in JS backend #211
• Replace stereum/nimbus docker images in JS backend #212
• Replace stereum/lighthouse docker images in molecule tests #213
• Replace stereum/nimbus docker images in molecule tests #214

[gbayasgalan]

#328