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/server/api/connect/v1/membership_resolvers.go

@@ -32,8 +32,7 @@ func (r *membershipResolver) LastSession(ctx context.Context, obj *types.Members
 
 	childSession, err := r.iam.SessionService.GetActiveSessionForMembership(ctx, session.ID, obj.ID)
 	if err != nil {
-		var errSessionNotFound *iam.ErrSessionNotFound
-		if errors.As(err, &errSessionNotFound) {
+		if _, ok := errors.AsType[*iam.ErrSessionNotFound](err); ok {
 			return nil, nil
 		}