Remote task scheduler complete

[atlas5301]

this is the complete version ov multi_machine_scheduler(with all components added) a full test is added in 90.multi_machine_schedule folder

[roastduck]

RPCTools can be renamed to rpc_tools.

[lgtm-com[bot]]

This pull request introduces 7 alerts when merging 86be6cd57c49138613a05586a8efda9af149b67c into 489c030f0674bf1e8f16a67b6106bd47a7ff5324 - view on LGTM.com

new alerts:

• 3 for Unused import
• 2 for Except block handles 'BaseException'
• 1 for 'import *' may pollute namespace
• 1 for Binding a socket to all network interfaces

[lgtm-com[bot]]

This pull request introduces 5 alerts when merging d869e00d4a24eeb3a3810ece85583c93b83a972a into 489c030f0674bf1e8f16a67b6106bd47a7ff5324 - view on LGTM.com

new alerts:

• 2 for Except block handles 'BaseException'
• 1 for Unused import
• 1 for 'import *' may pollute namespace
• 1 for Binding a socket to all network interfaces