[1.5] Within explore: Add support for searching TXID?

You can search by transaction id on [cryptofresh](http://cryptofresh.com/tx/79d247dae31448309aff3b955763c63a59e39cac) and soon [bitshares-explorer](http://bitshares-explorer.io:9009/#/txs), but the functionality doesn't exist within the Bitshares internal explore portal.

Would it be possible to include the txid within the in-client block details page, and have txid search in the explore portal? It's not stored in the CSV export, you can most likely get this information through a CLI client but that's a large hurdle for a non-tech savvy user.

Does cryptofresh generate these txid? I cannot see the txid value within the transaction's raw tx details ([on cryptofresh](http://cryptofresh.com/tx/79d247dae31448309aff3b955763c63a59e39cac)) nor within the client:


https://openledger.io/block/19672521

No source files or tests are named. Start by tracing the explore portal and the in-client block details page, then determine whether the transaction ID is available from the client or requires another source. Done means the block details expose the TXID and the explore portal can search by it.

Written by the indexing model from the issue text.