Pare down build scripts; naming consistancy

[ggetz]

Fixes #10313

This PR pares down the number of build command in favor of using flags with the build script as needed. It also makes sure naming conventions are consistant.

[cesium-concierge]

Thanks for the pull request @ggetz!

• ✔️ Signed CLA found.
• ❔ CHANGES.md was not updated.
  • If this change updates the public API in any way, please add a bullet point to CHANGES.md.
• ❔ Unit tests were not updated.
  • Make sure you've updated tests to reflect your changes, added tests for any new code, and ran the code coverage tool.

Reviewers, don't forget to make sure that:

• Cesium Viewer works.
• Works in 2D/CV.

[sanjeetsuhag]

@ggetz This is a good change. There's a few areas that still need to be updated:

• The generateDocumentation command is referenced in CesiumSandcastle.js and the Documentation Guide. We should document the build-docs-watch command somewhere.
• The buildApps command is referenced in the Performance Testing Guide.
• The makeZipFile command is referenced in the Release Guide in the Wiki.

[ggetz]

Thanks @sanjeetsuhag! I'll update the Release Guide after this PR. I think it may make sense to check this into the repo proper rather than the wiki so we don't have to make separate updates.

[sanjeetsuhag]

Thanks @ggetz!

(CI failures are unrelated and random so I'm merging)