Preparations for removing BaseDendrite (#3016)

Preparations to actually remove/replace `BaseDendrite`.
Quite a few changes:
- SyncAPI accepts an `fulltext.Indexer` interface (fulltext is removed
from `BaseDendrite`)
- Caches are removed from `BaseDendrite`
- Introduces a `Router` struct (likely to change)
  - also fixes #2903
- Introduces a `sqlutil.ConnectionManager`, which should remove
`base.DatabaseConnection` later on
- probably more

userapi/userapi.go

@@ -18,6 +18,7 @@ import (
 	"time"
 
 	fedsenderapi "github.com/matrix-org/dendrite/federationapi/api"
+	"github.com/matrix-org/dendrite/internal/pushgateway"
 	"github.com/sirupsen/logrus"
 
 	rsapi "github.com/matrix-org/dendrite/roomserver/api"
@@ -42,10 +43,11 @@ func NewInternalAPI(
 	js, _ := base.NATS.Prepare(base.ProcessContext, &cfg.Matrix.JetStream)
 	appServices := base.Cfg.Derived.ApplicationServices
 
-	pgClient := base.PushGatewayHTTPClient()
+	pgClient := pushgateway.NewHTTPClient(cfg.PushGatewayDisableTLSValidation)
 
 	db, err := storage.NewUserDatabase(
-		base,
+		base.ProcessContext.Context(),
+		base.ConnectionManager,
 		&cfg.AccountDatabase,
 		cfg.Matrix.ServerName,
 		cfg.BCryptCost,
@@ -57,7 +59,7 @@ func NewInternalAPI(
 		logrus.WithError(err).Panicf("failed to connect to accounts db")
 	}
 
-	keyDB, err := storage.NewKeyDatabase(base, &base.Cfg.KeyServer.Database)
+	keyDB, err := storage.NewKeyDatabase(base.ConnectionManager, &base.Cfg.KeyServer.Database)
 	if err != nil {
 		logrus.WithError(err).Panicf("failed to connect to key db")
 	}