Add query_txid plugin by leveldb

[bijianing97]

With this plugin, you can get transaction structure information through txid.
Features：

1. Save the transactions information in the irreversible blocks to leveldb.
2. Save the transactions information in the unconfirmed blocks to the db object trx_entry_object, and then move them to leveldb after being confirmed.
3. Provide get_transaction_by_txid(db api) to query transaction structure.

Performance：

1. Leveldb is a lightweight third-party database which does not require additional database processes to be started, just install related dependencies and integrate them.
2. Track all txids and only need little memory usage.

Dependence：

1. installLeveldb：

   wget https://github.com/google/leveldb/archive/v1.20.tar.gz
   tar xvf v1.20.tar.gz
   rm -f v1.20.tar.gz
   cd leveldb-1.20
   make
   sudo cp -r out-static/lib* out-shared/lib* "/usr/local/lib"
   cd include
   sudo cp -r leveldb /usr/local/include
   sudo ldconfig
   

2. install snappy

   git clone https://github.com/google/snappy.git
   cd snappy
   mkdir build
   cd build && cmake ../ 
   sudo make install
   

More：
https://docs.gxchain.org/zh/advanced/plugin_txid.html

Step：

1. Compile the new change

   git submodule update --init --recursive
   cmake .
   make
   

2. Start the witness with plugin

    ./witness_node --plugins "witness account_history query_txid"
   

3. Query the transaction by txid

curl --data '{
    "jsonrpc": "2.0",
        "method": "call",
        "params": [0, "get_transaction_by_txid", ["c4cb33ac91253147f5a0c426c1cb62fe8185ddb5"]],
        "id": 1
}' 127.0.0.1:28090 | json_pp

Example:

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current
                                 Dload  Upload   Total   Spent    Left  Speed
100  1111  100   948  100   163  67641  11630 --:--:-- --:--:-- --:--:-- 72923
{
   "result" : {
      "ref_block_prefix" : 93791064,
      "operation_results" : [
         [
            0,
            {}
         ]
      ],
      "operations" : [
         [
            6,
            {
               "fee" : {
                  "asset_id" : "1.3.0",
                  "amount" : 2017968
               },
               "account" : "1.2.22517",
               "active" : {
                  "weight_threshold" : 1,
                  "address_auths" : [],
                  "account_auths" : [],
                  "key_auths" : [
                     [
                        "BTS7piPcCkNano63VbgQq7RJh3xx5n61yWEC7PLrJ2vNVxGvZ2KYS",
                        1
                     ]
                  ]
               },
               "owner" : {
                  "key_auths" : [
                     [
                        "BTS7piPcCkNano63VbgQq7RJh3xx5n61yWEC7PLrJ2vNVxGvZ2KYS",
                        1
                     ]
                  ],
                  "weight_threshold" : 1,
                  "address_auths" : [],
                  "account_auths" : []
               },
               "extensions" : {},
               "new_options" : {
                  "memo_key" : "BTS7piPcCkNano63VbgQq7RJh3xx5n61yWEC7PLrJ2vNVxGvZ2KYS",
                  "extensions" : [],
                  "num_committee" : 0,
                  "voting_account" : "1.2.5",
                  "votes" : [
                     "1:22",
                     "1:24",
                     "1:25",
                     "1:27",
                     "1:28",
                     "1:29",
                     "1:30",
                     "1:32",
                     "1:33",
                     "1:36",
                     "1:38"
                  ],
                  "num_witness" : 11
               }
            }
         ]
      ],
      "ref_block_num" : 5294,
      "extensions" : [],
      "signatures" : [
         "1f62a2d3d9cc873f7cf4599a9df27e9521f3257cb723f791aa7e7f8c1e0ab5047d30e84394ecb71f03c593074b91a6ad095d95ce442ef985e0cb11717dd5873a4b"
      ],
      "expiration" : "2015-10-13T19:04:35"
   },
   "jsonrpc" : "2.0",
   "id" : 1
}

[pmconrad]

Thanks. Wrt performance, how does it affect replay speed?
Also, to my knowledge leveldb will rebalance its files sometimes, which could lead to unpredictable delays. This would be a no-go for witness nodes (and depending on delay length possibly for public API nodes as well), unless the leveldb-writing is decoupled from main operation.

[pmconrad]

Closing in favour of #1954