simple-adblock: update to 1.9.3-1

simple-adblock: update to 1.9.3-1

* introduce the new curl_max_file_size option
* prevent warnings/errors to be displayed each time the load_environment
  is invoked
* better organize dl_command appendixes
* implement support for downloading/using external dnsmasq config file
* refactor adb_check and adb_allow for better readability
* update default values for some options in the uci_load_validate call
* update reload trigger to include curl options

Signed-off-by: Stan Grishin <redacted>