Switch SASS Compiler to support Sourcemaps

[TiKevin83]

Sourcemaps would be a huge help to development of CSS resources, but WebOptimizer doesn't support them and didn't respond to my GitHub issue. We should switch to webpack or bare npm scripts so we can build sourcemaps, and I would suggest shipping them even to live since they only get loaded in devtools and the site is open source.

[nattthebear]

WebOptimizer was a nice quick win, but it doesn't seem to be well maintained. Hopefully we can do this with something other than Webpack.

[TiKevin83]

I have a branch going that fixes this but the package only works with dotnet run, trying to run in visual studio is throwing errors about System.Runtime assembly references

https://github.com/TiKevin83/tasvideos/tree/better-css-compilation