Trigger hourly build from scripted Jenkinsfile

You could use this snippet for Scripted pipeline syntax:

properties(
    [
        ...  , // other properties that you have
        pipelineTriggers([cron('0 * * * *')]),
    ]
)

Reference for properties is here. You can search for "pipelineTriggers" string and find out that triggers for build can be for example artifactory or something else from this list (extracted 2019-03-23 from linked doc page):

$class: 'ArtifactoryTrigger'
$class: 'AssemblaBuildTrigger'
bitBucketTrigger
bitbucketPush
$class: 'BuildResultTrigger'
$class: 'CIBuildTrigger'
$class: 'CodingPushTrigger'
$class: 'CronFolderTrigger'
$class: 'DeployDbTrigger'
$class: 'DockerHubTrigger'
$class: 'DosTrigger'
$class: 'ElOyente'
$class: 'FanInReverseBuildTrigger'
$class: 'FeatureBranchAwareTrigger'
$class: 'FilesFoundTrigger'
$class: 'FogbugzStatePoller'
$class: 'FolderContentTrigger'
GenericTrigger
gerrit
$class: 'GhprbTrigger'
$class: 'GitBucketPushTrigger'
githubBranches
githubPullRequests
githubPush
gitee
$class: 'GogsTrigger'
issueCommentTrigger
$class: 'IvyTrigger'
$class: 'JiraChangelogTrigger'
$class: 'JiraCommentTrigger'
$class: 'KanboardQueryTrigger'
$class: 'MailCommandTrigger'
$class: 'MavenDependencyUpdateTrigger'
$class: 'NugetTrigger'
p4Trigger
$class: 'PeriodicFolderTrigger'
$class: 'PollMailboxTrigger'
$class: 'PullRequestBuildTrigger'
$class: 'QuayIoTrigger'
$class: 'RemoteBuildTrigger'
upstream
$class: 'RundeckTrigger'
<code>scm</code>
$class: 'SelfieTrigger'
$class: 'SpoonTrigger'
$class: 'SqsBuildTrigger'
$class: 'TeamPRPushTrigger'
$class: 'TeamPushTrigger'
cron
$class: 'URLTrigger'
snapshotDependencies
$class: 'io.relution.jenkins.awssqs.SQSTrigger'
$class: 'io.relution.jenkins.scmsqs.SQSTrigger'
$class: 'org.cloudbees.literate.jenkins.promotions.PromotionTrigger'
$class: 'org.jenkinsci.plugins.deploy.weblogic.trigger.DeploymentTrigger'
$class: 'org.jenkinsci.plugins.deployment.DeploymentTrigger'

More info about scripted way here (sample from another question). Documentation that covers declarative pipeline is here.