Enforce Go style rules across codebase

Apply five style rules: convert iota string enums to typed
string constants, replace errors.As with errors.AsType,
merge three-group imports into two groups, fix multiline
parameter/argument formatting, and replace fmt.Sprintf URL
construction with net/url.

Signed-off-by: Émile Ré <emile@probo.com>

pkg/coredata/document_default_approver.go

@@ -130,13 +130,16 @@ WHEN NOT MATCHED BY SOURCE
 
 	result := make(DocumentDefaultApprovers, 0, len(approverProfileIDs))
 	for _, profileID := range approverProfileIDs {
-		result = append(result, &DocumentDefaultApprover{
-			DocumentID:        documentID,
-			ApproverProfileID: profileID,
-			OrganizationID:    organizationID,
-			CreatedAt:         now,
-			UpdatedAt:         now,
-		})
+		result = append(
+			result,
+			&DocumentDefaultApprover{
+				DocumentID:        documentID,
+				ApproverProfileID: profileID,
+				OrganizationID:    organizationID,
+				CreatedAt:         now,
+				UpdatedAt:         now,
+			},
+		)
 	}
 
 	*das = result