compute_tools: support gRPC base backups in compute_ctl (#12244)

## Problem

`compute_ctl` should support gRPC base backups.

Requires #12111.
Requires #12243.
Touches #11926.

## Summary of changes

Support `grpc://` connstrings for `compute_ctl` base backups.

Cargo.lock

@@ -1316,6 +1316,7 @@ dependencies = [
  "opentelemetry",
  "opentelemetry_sdk",
  "p256 0.13.2",
+ "pageserver_page_api",
  "postgres",
  "postgres_initdb",
  "postgres_versioninfo",
@@ -1335,6 +1336,7 @@ dependencies = [
  "tokio-postgres",
  "tokio-stream",
  "tokio-util",
+ "tonic 0.13.1",
  "tower 0.5.2",
  "tower-http",
  "tower-otel",
@@ -4475,12 +4477,13 @@ dependencies = [
  "bytes",
  "futures",
  "pageserver_api",
- "postgres_ffi",
+ "postgres_ffi_types",
  "prost 0.13.5",
  "strum",
  "strum_macros",
  "thiserror 1.0.69",
  "tokio",
+ "tokio-util",
  "tonic 0.13.1",
  "tonic-build",
  "utils",
@@ -8679,7 +8682,6 @@ dependencies = [
  "num-iter",
  "num-rational",
  "num-traits",
- "once_cell",
  "p256 0.13.2",
  "parquet",
  "prettyplease",