build: add material experimental package

[devversion]

• Adds the material-experimental package.
• Speeds up the AOT task by no longer copying the release directories (follow-up for e2e app)
• No longer rebuilds everything on changes (demo-app serving)

@jelbourn Everything passed in the CI, just the IE11 failure that Kristiyan mentioned is causing the red status.

[jelbourn]

LGTM

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