support view as a independent unit of leading hint
add random test check of leading hint query
add more test with data of leading hint query
add random test check of distribute hint
### Motivation
TABLESAMPLE allows you to limit the number of rows from a table in the FROM clause.
Used for data detection, quick verification of the accuracy of SQL, table statistics collection.
### Grammar
```
[TABLET tids] TABLESAMPLE n [ROWS | PERCENT] [REPEATABLE seek]
```
Limit the number of rows read from the table in the FROM clause,
select a number of Tablets pseudo-randomly from the table according to the specified number of rows or percentages,
and specify the number of seeds in REPEATABLE to return the selected samples again.
In addition, can also manually specify the TableID,
Note that this can only be used for OLAP tables.
### Example
Q1:
```
SELECT * FROM t1 TABLET(10001,10002) limit 1000;
```
explain:
```
partitions=1/1, tablets=2/12, tabletList=10001,10002
```
Select the specified tabletID of the t1.
Q2:
```
SELECT * FROM t1 TABLESAMPLE(1000000 ROWS) REPEATABLE 1 limit 1000;
```
explain:
```
partitions=1/1, tablets=3/12, tabletList=10001,10002,10003
```
Q3:
```
SELECT * FROM t1 TABLESAMPLE(1000000 ROWS) REPEATABLE 2 limit 1000;
```
explain:
```
partitions=1/1, tablets=3/12, tabletList=10002,10003,10004
```
Pseudo-randomly sample 1000 rows in t1.
Note that several Tablets are actually selected according to the statistics of the table,
and the total number of selected Tablet rows may be greater than 1000,
so if you want to explicitly return 1000 rows, you need to add Limit.
### Design
First, determine how many rows to sample from each partition according to the number of partitions.
Then determine the number of Tablets to be selected for each partition according to the average number of rows of Tablet,
If seek is not specified, the specified number of Tablets are pseudo-randomly selected from each partition.
If seek is specified, it will be selected sequentially from the seek tablet of the partition.
And add the manually specified Tablet id to the selected Tablet.
In order to cooperate with Doris's successful graduation from Apache, the Doris official website also needs a new look
and more powerful feature, so we decided to redesign the Doris official website.
The code and documents of the new official website are included in this PR.
Since the new website is completely rewritten, the content and structure of the project are different from the previous one.
In particular, the directory structure of documents has changed, and the number of documents is large, so the number of
files in this PR is very large.
In the old website，all English documents are in the en/ directory, and Chinese documents in the zh-CN/ directory,
but in the new website，the documents are split into multiple directories according to the nav.
The document's directory structure changes as follows：
```
docs (old website)
| |—— .vuepress (library)
| |—— en
| | |—— admin-manual
│ │ |—— advanced
| | |—— article
| | |—— benchmark
| | |—— case-user
| | |—— community
| | |—— data-operate
| | |—— data-table
| | |—— design
| | |—— developer-guide
| | |—— downloads
| | |—— ecosystem
| | |—— faq
| | |—— get-starting
| | |—— install
| | |—— sql-manual
| | |—— summary
| | |___ README.md
| |—— zh-CN
...
docs (new website)
| |—— .vuepress (library)
| |—— en
| | |—— community (unchanged, community nav)
│ │ |—— developer (new directory, developer nav)
│ │ | |—— design (moved from en/design)
│ │ | |__ developer-guide (moved from en/developer-guide)
| | |—— docs (new directory, all children directories moved from en/, document nav)
│ │ | |—— admin-manual
│ │ | |—— advanced
│ │ | |—— benchmark
│ │ | |—— data-operate
│ │ | |—— data-table
│ │ | |—— ecosystem
│ │ | |—— faq
│ │ | |—— get-starting
│ │ | |—— install
│ │ | |—— sql-manual
│ │ | |—— summary
| | |—— downloads (unchanged, downloads nav)
| | |—— userCase (moved from en/case-user, user nav)
| | |___ README.md
| |—— zh-CN
...
```
