Decrease coupling between services

Previously, the different services had many unnesscary dependencies,
such as the database cannot run without cleanup, and that the it cannot
accept BEP uploads without starting the gRPC BES server, and Graphql
API. This change removes many unnesscary dependencies and decreases the
coupling between different services.

Some of the changes:

- Reorganizes bb_portal.proto
- Moves the database and database cleanup configuration to its own top
  level configuration.
- Separate BES/BEP uploading and the Graphql API into two different
  services.
- Replace instanceNameAuthorizer with individual authorizers for each
  service and blob access.
- Make it possible to
    - not serve the frontend
    - not serve the graphql api
    - run without database cleanup
    - run without a http server
    - run without the BES gRPC server
    - run database cleanup without the BES

Author: isakstenstrom

cmd/bb_portal/BUILD.bazel

@@ -7,21 +7,34 @@ go_library(
     importpath = "github.com/buildbarn/bb-portal/cmd/bb_portal",
     visibility = ["//visibility:private"],
     deps = [
+        "//ent/gen/ent/migrate",
         "//ent/gen/ent/runtime",
+        "//internal/api/http/graphql_api_service",
         "//internal/api/http/zstdmiddleware",
         "//internal/bep",
+        "//internal/database",
+        "//internal/database/common",
+        "//internal/database/dbcleanupservice",
         "//pkg/frontend",
         "//pkg/grpcweb/blobstoreservice",
         "//pkg/grpcweb/schedulerservice",
+        "//pkg/prometheus_metrics",
         "//pkg/proto/configuration/bb_portal",
+        "@com_github_buildbarn_bb_storage//pkg/auth",
         "@com_github_buildbarn_bb_storage//pkg/auth/configuration",
+        "@com_github_buildbarn_bb_storage//pkg/blobstore",
+        "@com_github_buildbarn_bb_storage//pkg/blobstore/configuration",
+        "@com_github_buildbarn_bb_storage//pkg/clock",
+        "@com_github_buildbarn_bb_storage//pkg/digest",
         "@com_github_buildbarn_bb_storage//pkg/global",
+        "@com_github_buildbarn_bb_storage//pkg/grpc",
         "@com_github_buildbarn_bb_storage//pkg/http/server",
         "@com_github_buildbarn_bb_storage//pkg/program",
         "@com_github_buildbarn_bb_storage//pkg/util",
         "@com_github_buildbarn_bb_storage//pkg/zstd",
         "@io_opentelemetry_go_contrib_instrumentation_net_http_otelhttp//:otelhttp",
         "@io_opentelemetry_go_otel//:otel",
+        "@io_opentelemetry_go_otel_trace//:trace",
         "@org_golang_google_grpc//codes",
         "@org_golang_google_grpc//status",
     ],