[performance] cache recently allowed/denied domains to cut down on db calls (#794)

* fetch creation and fetching domain blocks from db

Signed-off-by: kim <grufwub@gmail.com>

* add separate domainblock cache type, handle removing block from cache on delete

Signed-off-by: kim <grufwub@gmail.com>

* fix sentinel nil values being passed into cache

Signed-off-by: kim <grufwub@gmail.com>

Signed-off-by: kim <grufwub@gmail.com>

internal/db/bundb/domain_test.go

@@ -21,6 +21,7 @@ package bundb_test
 import (
 	"context"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/suite"
 	"github.com/superseriousbusiness/gotosocial/internal/gtsmodel"
@@ -33,10 +34,15 @@ type DomainTestSuite struct {
 func (suite *DomainTestSuite) TestIsDomainBlocked() {
 	ctx := context.Background()
 
+	now := time.Now()
+
 	domainBlock := &gtsmodel.DomainBlock{
 		ID:                 "01G204214Y9TNJEBX39C7G88SW",
 		Domain:             "some.bad.apples",
+		CreatedAt:          now,
+		UpdatedAt:          now,
 		CreatedByAccountID: suite.testAccounts["admin_account"].ID,
+		CreatedByAccount:   suite.testAccounts["admin_account"],
 	}
 
 	// no domain block exists for the given domain yet
@@ -44,7 +50,8 @@ func (suite *DomainTestSuite) TestIsDomainBlocked() {
 	suite.NoError(err)
 	suite.False(blocked)
 
-	suite.db.Put(ctx, domainBlock)
+	err = suite.db.CreateDomainBlock(ctx, *domainBlock)
+	suite.NoError(err)
 
 	// domain block now exists
 	blocked, err = suite.db.IsDomainBlocked(ctx, domainBlock.Domain)