[Feature] Introduce Session Interface

[s7monk]

Relates to: #195

Purpose

This pull request is a subtask implementation of #195, which introduces a session interface that creates a session or triggers a heartbeat of session.

Tests

SessionControllerTest

API and Format

@PostMapping("/check")
    public R<Void> checkAndRenewSession(Integer uid) {
        QueryWrapper<ClusterInfo> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("type", "Flink");
        List<ClusterInfo> clusterInfos = clusterService.list(queryWrapper);
        for (ClusterInfo cluster : clusterInfos) {
            SessionDTO sessionDTO = new SessionDTO();
            sessionDTO.setHost(cluster.getHost());
            sessionDTO.setPort(cluster.getPort());
            sessionDTO.setClusterId(cluster.getId());
            sessionDTO.setUid(uid);
            if (sessionService.getSession(uid, cluster.getId()) == null) {
                sessionService.createSession(sessionDTO);
            } else {
                if (sessionService.triggerSessionHeartbeat(sessionDTO) < 1) {
                    sessionService.createSession(sessionDTO);
                }
            }
        }
        return R.succeed();
    }