feat: introduce executor v2 for the new planner

[wangrunji0408]

This PR starts migrating executors to the new planner. The new version is put into a new module executor_v2. This PR finishes the migration of scan, projection, filter, and explain executor. Now the new planner is able to work from end to end!

> \v2
switched to planner v2
in 0.000s
> select * from nation where N_NATIONKEY = 24;
+----+---------------+---+----------------------------------------------------------------------------------------------------------------+
| 24 | UNITED STATES | 1 | y final packages. slow foxes cajole quickly. quickly silent platelets breach ironic accounts. unusual pinto be |
+----+---------------+---+----------------------------------------------------------------------------------------------------------------+
in 0.067s
> explain select * from nation where N_NATIONKEY = 24;
+--------------------------------------------------+
| Projection: [$0.0, $0.1, $0.2, $0.3] (cost=6000) |
|   Filter: ($0.0 = 24) (cost=5100)                |
|     Scan: [$0.0, $0.1, $0.2, $0.3] (cost=4000)   |
|                                                  |
+--------------------------------------------------+
in 0.036s