Remove unneeded peers

[mkszepp]

• ember-source: removed because the embroider / auto-import know what we intend - it's not bad to have if someone manages their dep graph correctly, which is easier with pnpm, but not everyone gets it right, and folks have a hard time tracking down errors
• @glimmer/tracking removed because it's a real package, but one we don't want to use. This comes up in embroider/vite where the presence of real packages always takes precedence over virtual packages. This is actually problematic because it can break reactivity in subtle ways, even if a dep graph is correct - allowing duplicates of dependencies, which for the glimmer internals, we don't want.

ref ember-cli/ember-addon-blueprint#35