Update image and sound filenames so they can be JS names

[samreid]

Follow the ideas according to https://github.com/phetsims/chipper/issues/1060#issuecomment-898662534

Repos I'm responsible for. Check means done or not applicable:

• [x] axon
• [x] bamboo
• [x] beaker
• [x] bending-light
• [x] blast
• [x] circuit-construction-ios-app
• [x] circuit-construction-kit-ac
• [x] circuit-construction-kit-ac-virtual-lab
• [x] circuit-construction-kit-basics
• [x] circuit-construction-kit-black-box-study
• [x] circuit-construction-kit-common
• [x] circuit-construction-kit-dc
• [x] circuit-construction-kit-dc-virtual-lab
• [x] decaf
• [x] eating-exercise-and-energy
• [x] fraction-comparison
• [x] gravity-and-orbits
• [x] griddle
• [x] protein-synthesis
• [x] seasons
• [x] sherpa
• [x] sugar-and-salt-solutions
• [x] under-pressure
• [x] wave-interference
• [x] waves-intro

[samreid]

I'd like to wait for https://github.com/phetsims/chipper/issues/1079 before I start on this. Putting on hold.

[samreid]

Wave Interference images already used underscores, so I left those in place. I did not update anything that wasn't in active repos. Everything else is done, closing.