feat(rover): asyncification

[aaronArinder]

notes

• takes @Geal's branch, fixes tests, and merges main
• ⚠️ I've adding WARNINGs in places I think we should sanity check
• ⚠️ ❗our test coverage isn't good enough to count passing tests as a sure sign of a safe migration ❗ ⚠️
• rover dev seems to work as expected except for shutting down:

 ✘ aaronarinder@Aarons-MBP  ~/apollo/rover/examples/supergraph-demo   aaron/my-rover-is-purple ±  
cargo r -- dev --supergraph-config ./supergraph.yaml          ~/apollo/rover/examples/supergraph-demo
   Compiling rover v0.25.0-rc.0 (/Users/aaronarinder/apollo/rover)
    Finished `dev` profile [unoptimized + debuginfo] target(s) in 7.84s
     Running `/Users/aaronarinder/apollo/rover/target/debug/rover dev --supergraph-config ./supergraph
.yaml`
⚠️  Do not run this command in production! ⚠️  It is intended for local development.
🛫 starting a session with the 'pandas' subgraph
🛫 starting a session with the 'products' subgraph
🛫 starting a session with the 'users' subgraph
👀 watching ./pandas/pandas.graphql for changes
👀 watching ./products/products.graphql for changes
🎶 composing supergraph with Federation v2.8.2
WARN: telemetry.instrumentation.spans.mode is currently set to 'deprecated', either explicitly or via 
defaulting. Set telemetry.instrumentation.spans.mode explicitly in your router.yaml to 'spec_compliant
' for log and span attributes that follow OpenTelemetry semantic conventions. This option will be defa
ulted to 'spec_compliant' in a future release and eventually removed altogether
🚀 your supergraph is running! head to http://localhost:4000 to query your supergraph
✅ successfully composed after adding the 'users' subgraph
👀 watching ./users/users.graphql for changes
^C
✋ shutting down the `rover dev` session and all attached processes...
 ✘ aaronarinder@Aarons-MBP  ~/apollo/rover/examples/supergraph-demo   aaron/my-rover-is-purple ±  

• supergraph compose also works, and looks pretty snappy compared to its previous version when run against 100 subgraphs (we'll test with more; this is meant to show that it's directionally correct):

 aaronarinder@Aarons-MBP  ~/apollo/rover  ↱ aaron/my-rover-is-purple  time APOLLO_REGISTRY_URL="
https://api-staging.apollographql.com/graphql" cargo r --release --bin rover -- supergraph compose 
--profile staging-test --config ../performance-subgraphs/schemas/supergraph.yaml

[...]

APOLLO_REGISTRY_URL="https://api-staging.apollographql.com/graphql" cargo r    8.55s user 0.84s sys
tem 99% cpu 9.442 total

[aaronArinder]

closing in favor of #2035