Fix for get_input_type endpoint, new params in witness apis

1. Fix for bug in get_input_type - when account_name was provided it didn't return array of similar account names.

2. #77 (closed) Add parameters last_confirmed_block_num and account_creation_fee to witness apis (/witnesses and /witnesses/{account-name}) - params were added to sync - existing hafbe nodes require resync.

3. Add timestamp of last cache update - it add context to witness api response (votes are being updated every 10 minutes, it allows to show how "old" is showcased data)