[Enhancement](llm) Support some LLM functions

docs/sql-manual/sql-functions/scalar-functions/llm-functions/llm-classify.md

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+---
+{
+    "title": "LLM_CLASSIFY",
+    "language": "en"
+}
+---
+
+<!-- 
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you under the Apache License, Version 2.0 (the
+"License"); you may not use this file except in compliance
+with the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing,
+software distributed under the License is distributed on an
+"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, either express or implied.  See the License for the
+specific language governing permissions and limitations
+under the License.
+-->
+
+## Description
+
+Used to classify text into a specified set of labels.
+
+## Syntax
+
+```sql
+LLM_CLASSIFY([<resource_name>], <text>, <labels>)
+```
+
+## Parameters
+
+|    Parameter      | Description                                 |
+| ----------------- | ------------------------------------------- |
+| `<resource_name>` | The specified resource name, optional       |
+| `<text>`          | The text to be classified                   |
+| `<labels>`        | Array of classification labels              |
+
+## Return Value
+
+Returns the single label that best matches the text.
+
+If any input is NULL, returns NULL.
+
+The result is generated by a large language model, so the output may vary.
+
+## Examples
+
+```sql
+SET default_llm_classify_resource = 'resource_name';
+SELECT LLM_CLASSIFY('Apache Doris is a databases system.', ['useage', 'introduce']) AS Result;
+```
+```text
++-----------+
+| Result    |
++-----------+
+| introduce |
++-----------+
+```
+
+```sql
+SELECT LLM_CLASSIFY('resource_name', 'Apache Doris is developing rapidly.', ['science', 'sport']) AS Result;
+```
+```text
++---------+
+| Result  |
++---------+
+| science |
++---------+
+```

docs/sql-manual/sql-functions/scalar-functions/llm-functions/llm-extract.md

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+---
+{
+    "title": "LLM_EXTRACT",
+    "language": "en"
+}
+---
+
+<!-- 
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you under the Apache License, Version 2.0 (the
+"License"); you may not use this file except in compliance
+with the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing,
+software distributed under the License is distributed on an
+"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, either express or implied.  See the License for the
+specific language governing permissions and limitations
+under the License.
+-->
+
+## Description
+
+Used to extract information corresponding to specific labels from text.
+
+## Syntax
+
+```sql
+LLM_EXTRACT([<resource_name>], <text>, <labels>)
+```
+
+## Parameters
+
+|    Parameter      | Description                                  |
+| ----------------- | -------------------------------------------- |
+| `<resource_name>` | The specified resource name, optional        |
+| `<text>`          | The text from which to extract information   |
+| `<labels>`        | Array of labels to extract                   |
+
+## Return Value
+
+Returns a string containing all extracted labels and their corresponding values.
+
+If any input is NULL, returns NULL.
+
+The result is generated by a large language model, so the output may vary.
+
+## Examples
+
+```sql
+SET default_llm_extract_resource = 'resource_name';
+SELECT LLM_EXTRACT('Apache Doris is an MPP-based real-time data warehouse known for its high query speed.', 
+                  ['product_name', 'architecture', 'key_feature']) AS Result;
+```
+```text
++---------------------------------------------------------------------------------------+
+| Result                                                                                |
++---------------------------------------------------------------------------------------+
+| product_name="Apache Doris", architecture="MPP-based", key_feature="high query speed" |
++---------------------------------------------------------------------------------------+
+```
+
+```sql
+SELECT LLM_EXTRACT('resource_name', 'Apache Doris began in 2008 as an internal project named Palo.',
+                  ['original name', 'founding time']) AS Result;
+```
+```text
++----------------------------------------+
+| Result                                 |
++----------------------------------------+
+| original name=Palo, founding time=2008 |
++----------------------------------------+
+```

docs/sql-manual/sql-functions/scalar-functions/llm-functions/llm-fixgrammar.md

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+---
+{
+    "title": "LLM_FIXGRAMMAR",
+    "language": "en"
+}
+---
+
+<!-- 
+Licensed to the Apache Software Foundation (ASF) under one
+or more contributor license agreements.  See the NOTICE file
+distributed with this work for additional information
+regarding copyright ownership.  The ASF licenses this file
+to you under the Apache License, Version 2.0 (the
+"License"); you may not use this file except in compliance
+with the License.  You may obtain a copy of the License at
+
+  http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing,
+software distributed under the License is distributed on an
+"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
+KIND, either express or implied.  See the License for the
+specific language governing permissions and limitations
+under the License.
+-->
+
+## Description
+
+Used to correct grammatical errors in text.
+
+## Syntax
+
+```sql
+LLM_FIXGRAMMAR([<resource_name>], <text>)
+```
+
+## Parameters
+
+|    Parameter      | Description                                 |
+| ----------------- | ------------------------------------------- |
+| `<resource_name>` | The specified resource name, optional       |
+| `<text>`          | The text to be grammar-corrected            |
+
+## Return Value
+
+Returns the text string after grammar correction.
+
+If any input is NULL, returns NULL.
+
+The result is generated by a large language model, so the output may vary.
+
+## Examples
+
+```sql
+SET default_llm_fixgrammar_resource = 'resource_name';
+SELECT LLM_FIXGRAMMAR('Apache Doris a great system DB') AS Result;
+```
+```text
++------------------------------------------+
+| Result                                   |
++------------------------------------------+
+| Apache Doris is a great database system. |
++------------------------------------------+
+```
+
+```sql
+SELECT LLM_FIXGRAMMAR('resource_name', 'I am like to using Doris') AS Result;
+```
+```text
++--------------------+
+| Result             |
++--------------------+
+| I like using Doris |
++--------------------+
+```