Description of problem:
The connection between Foreman Proxy and the Smart_proxy_dynflow_core is timed out(60 seconds) even we increased the "proxy_request_timeout" setting from the Satellite. It is because the setting is for the connection between Foreman and the Foreman Proxy. The connection between Foreman Proxy and Smart_proxy_dynflow_core is still 60 seconds (Net::HTTP default). 


Steps to Reproduce:
1. Satellite Web UI Administer -> Settings -> General tab -> Capsule request timeout -> Set to 600
2. Ensure foreman tasks batch triggering is On.
3. To simulate a task taking long time to trigger. Hack the following code to sleep for 300 seconds.

In "/opt/theforeman/tfm/root/usr/share/gems/gems/smart_proxy_dynflow_core-0.2.6/lib/smart_proxy_dynflow_core/api.rb"
    post "/tasks/launch/?" do
      sleep 300    <============== Add this line
      params = MultiJson.load(request.body.read)
      launcher = launcher_class(params).new(world, callback_host(params, request), params.fetch('options', {}))
      launcher.launch!(params['input'])
      launcher.results.to_json
    end

4. Restart foreman-proxy

systemctl restart foreman-proxy

5. Trigger any REX job against multiple hosts.

Actual results:
Parent task gets 500 Internal Server Error and the hosts' job hang forever.

Expected results:
No timed out occur. Add a setting to adjust the foreman-proxy timeout as needed.


Additional info:

# Dynflow parent Task
Error:
RestClient::InternalServerError
500 Internal Server Error
---
- "/opt/theforeman/tfm/root/usr/share/gems/gems/rest-client-2.0.2/lib/restclient/abstract_response.rb:223:in
  `exception_with_response'"
- "/opt/theforeman/tfm/root/usr/share/gems/gems/rest-client-2.0.2/lib/restclient/abstract_response.rb:103:in
  `return!'"
- "/opt/theforeman/tfm/root/usr/share/gems/gems/rest-client-2.0.2/lib/restclient/request.rb:809:in
  `process_result'"
- "/opt/theforeman/tfm/root/usr/share/gems/gems/rest-client-2.0.2/lib/restclient/request.rb:725:in
  `block in transmit'"
- "/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:910:in `start'"


# proxy.log
2021-04-26T13:47:14 d487df31 [I] Started POST /dynflow/tasks/launch 
2021-04-26T13:47:14 d487df31 [D] verifying remote client hao-satellite66.usersys.redhat.com (based on SSL_CLIENT_CERT) against trusted_hosts ["hao-satellite66.usersys.redhat.com"]
2021-04-26T13:47:14 d487df31 [D] Proxy request from hao-satellite66.usersys.redhat.com:9090/dynflow/tasks/launch to https://hao-satellite66.usersys.redhat.com:8008/tasks/launch
2021-04-26T13:48:14 d487df31 [W] Error processing request 'd487df31-a370-49eb-9971-d96ad46c4235: <Net::ReadTimeout>: Net::ReadTimeout
/opt/rh/rh-ruby25/root/usr/share/ruby/net/protocol.rb:181:in `rbuf_fill'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/protocol.rb:157:in `readuntil'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/protocol.rb:167:in `readline'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http/response.rb:40:in `read_status_line'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http/response.rb:29:in `read_new'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:1497:in `block in transport_request'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:1494:in `catch'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:1494:in `transport_request'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:1467:in `request'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:1460:in `block in request'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:910:in `start'
/opt/rh/rh-ruby25/root/usr/share/ruby/net/http.rb:1458:in `request'
/usr/share/foreman-proxy/lib/proxy/request.rb:48:in `send_request'
...

# Smart proxy dynflow core log
[26/Apr/2021:13:47:14 AEST] "POST /tasks/launch? HTTP/1.1" 200 0  <==== return 0 body length