Create PoC of generalized ClickHouse events storage.

Summary

Provide a PoC of a single table for all usage events in ClickHouse and PG.

# PG
CREATE TABLE ai_usage_events (
    id bigint NOT NULL,
    "timestamp" timestamp with time zone NOT NULL,
    user_id bigint NOT NULL,
    created_at timestamp with time zone NOT NULL,
    event smallint NOT NULL,
    organization_id bigint NOT NULL,
    namespace_path text,
    extras jsonb,
    CONSTRAINT check_628cdfbf3f CHECK ((char_length(namespace_path) <= 255))
)
PARTITION BY RANGE ("timestamp");

# CH 
CREATE TABLE ai_usage_events
(
    `user_id` UInt64 DEFAULT 0,
    `event` UInt8 DEFAULT 0,
    `namespace_path` String DEFAULT '0/',
    `timestamp` DateTime64(6, 'UTC') DEFAULT now64(),
    `extras` String
)
ENGINE = ReplacingMergeTree
PARTITION BY toYear(timestamp)
ORDER BY (namespace_path, user_id, event, timestamp)
SETTINGS index_granularity = 8192;

Verify that full E2E process works by migrated TroubleshootJobEvent class.