Update Sqlite UPDATE and INSERT logic to use ON CONFLICT

[franciscojavierarceo]

Is your feature request related to a problem? Please describe.
Migrate from this redundant code:

conn.execute(
    f"""
        UPDATE {table_name}
        SET value = ?, event_ts = ?, created_ts = ?
        WHERE (entity_key = ? AND feature_name = ?)
    """,
    (
        # SET
        val.SerializeToString(),
        timestamp,
        created_ts,
        # WHERE
        entity_key_bin,
        feature_name,
    ),
)

conn.execute(
    f"""INSERT OR IGNORE INTO {table_name}
        (entity_key, feature_name, value, event_ts, created_ts)
        VALUES (?, ?, ?, ?, ?)""",
    (
        entity_key_bin,
        feature_name,
        val.SerializeToString(),
        timestamp,
        created_ts,
    ),
)

To

conn.execute(
    f"""
    INSERT INTO {table_name} (entity_key, feature_name, value, event_ts, created_ts)
    VALUES (?, ?, ?, ?, ?)
    ON CONFLICT(entity_key, feature_name) DO UPDATE SET
        value = excluded.value,
        event_ts = excluded.event_ts,
        created_ts = excluded.created_ts;
    """,
    (
        entity_key_bin,          # entity_key
        feature_name,            # feature_name
        val.SerializeToString(), # value
        timestamp,               # event_ts
        created_ts               # created_ts
    ),
)

Describe the solution you'd like
Update with this code

Describe alternatives you've considered
N/A

Additional context
Should do this for sqlite-vec use cases too.