Drop unused tables

[zmcNotafraid]

sql = "select
  table_name,
  pg_size_pretty(pg_total_relation_size(quote_ident(table_name))),
  pg_total_relation_size(quote_ident(table_name))
from information_schema.tables
where table_schema = 'public'
order by 3 desc;"

[{"table_name"=>"pool_transaction_entries", "pg_size_pretty"=>"265 GB", "pg_total_relation_size"=>284052865024},
 {"table_name"=>"cell_outputs", "pg_size_pretty"=>"167 GB", "pg_total_relation_size"=>178790227968},
 {"table_name"=>"old_ckb_transactions", "pg_size_pretty"=>"112 GB", "pg_total_relation_size"=>120526061568},
 {"table_name"=>"witnesses", "pg_size_pretty"=>"102 GB", "pg_total_relation_size"=>109386489856},
 {"table_name"=>"cell_inputs_old", "pg_size_pretty"=>"39 GB", "pg_total_relation_size"=>41864544256},
 {"table_name"=>"cell_inputs", "pg_size_pretty"=>"37 GB", "pg_total_relation_size"=>39659905024},
 {"table_name"=>"cell_dependencies", "pg_size_pretty"=>"33 GB", "pg_total_relation_size"=>34984050688},
 {"table_name"=>"lock_scripts", "pg_size_pretty"=>"29 GB", "pg_total_relation_size"=>31015026688},
 {"table_name"=>"cell_data", "pg_size_pretty"=>"21 GB", "pg_total_relation_size"=>22473228288},
 {"table_name"=>"ckb_transactions_committed", "pg_size_pretty"=>"20 GB", "pg_total_relation_size"=>21605302272},
 {"table_name"=>"account_books", "pg_size_pretty"=>"17 GB", "pg_total_relation_size"=>18486534144},
 {"table_name"=>"addresses", "pg_size_pretty"=>"17 GB", "pg_total_relation_size"=>17884192768},
 ...

From the results we can see that the biggest size table was not used anymore, but it takes a lot of space in the database.So I will remove these tables from database.

[zmcNotafraid]

PR: nervosnetwork/ckb-explorer#1759