Ticket 72 handle IMA 2 IMA net errors

[sergiy-skalelabs]

IMA uses express-based HTTP server to deliver IMA-2-IMA notifications like PWA state tracking. This PR fixes network connection problems by adding error handlers. Express-related code also ported from JS into TypeScript. No performance changes expected.
It's barely possible to cover all possible network problems with unit-tests, especially when connection problem appear after JSON request received and before answer is sent. Such errors can have guaranteed emulation only with modified source code of IMA Agent where network socket is manually damaged.

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New version's testing sequence and expected result on dev net is:

• disable Main Net connectivity on selected node
• restart IMA Agent
• wait 20-30 minutes
• expect normal shutdown of IMA Agent with exit code 163
• expect no network errors and crashes in log output all this time

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Old buggy version's notes:

• use same testing sequence
• expect crash of IMA Agent with network timeout error and no normal call stack
• crash normally occur in less than 5 minutes
• crash does not change exit code to 163