feat(query): Support access Redis data from dictionaries via the `dict_get` function.

I hereby agree to the terms of the CLA available at: https://docs.databend.com/dev/policies/cla/

Summary

This pull request introduces support for accessing Redis data from dictionaries using the dict_getfunction. Other source like MySQL, PostgreSQL will be introduced in the future PRs.

Dictionary Creation with Redis Source:

CREATE OR REPLACE DICTIONARY d(key string not null, value string not null) PRIMARY KEY key SOURCE(redis(host='127.0.0.1' port='6379'))

options are used to provide the Redis connection URL, host and port are required options, and username, password, db_index are optional options.

connect to Redis and set some test keys and values

redis-cli -h 127.0.0.1 -p 6379
127.0.0.1:6379> set a abc
OK
127.0.0.1:6379> set b def
OK
127.0.0.1:6379>

Data Access with dict_get Function:

MySQL [(none)]> create or replace table t(a string);
Query OK, 0 rows affected (0.201 sec)

MySQL [(none)]> insert into t values('a'),('b'),('c');
Query OK, 3 rows affected (0.095 sec)

MySQL [(none)]> select a, dict_get(d, 'value', a) from t;
+------+---------------------------------+
| a | dict_get(default.d, 'value', a) |
+------+---------------------------------+
| a | abc |
| b | def |
| c | |
+------+---------------------------------+
3 rows in set (0.173 sec)

The result corresponds to the value stored in Redis associated with the keys in table column a.
If the key is not exists in the Redis, a default value will be inserted instead.

This PR also introduces a mock_source, which simulates a Redis server to test the dict_get function. Future work will expand this mock data source functionality to include support for other sources such as MySQL, PostgreSQL, and more.

part of https://github.com/datafuselabs/databend/issues/15901

Tests

[x] Unit Test
[ ] Logic Test
[ ] Benchmark Test
[ ] No Test - Explain why

Type of change

[ ] Bug Fix (non-breaking change which fixes an issue)
[x] New Feature (non-breaking change which adds functionality)
[ ] Breaking Change (fix or feature that could cause existing functionality not to work as expected)
[ ] Documentation Update
[ ] Refactoring
[ ] Performance Improvement
[ ] Other (please describe):

This change is

databendlabs / databend