refactor imports and fix oxo should exit once the scan has completed

[elyousfi5]

Test approach:

built an agent and tried to import some modules that were failing before:

built some agents (nmap, autoscaler, virustotal) with this version of oxo and ran scan with them:

AgentGroup:

name: test_oxo
kind: AgentGroup
description: Agent group definition for oxo testing.
agents:
  - args: [ ]
    key: agent/dev/nmap
  - args: [ ]
    key: agent/dev/virustotal
  - args: [ ]
    key: agent/dev/autoscaler

Logs of agents:

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 84.72222% with 11 lines in your changes missing coverage. Please review.

Project coverage is 80.33%. Comparing base (8205b10) to head (bfdba32). Report is 13 commits behind head on main.

Files	Patch %	Lines
src/ostorlab/main.py	0.00%	10 Missing :warning:
src/ostorlab/runtimes/local/log_streamer.py	90.00%	1 Missing :warning:

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #783 +/- ## =========================================== + Coverage 62.63% 80.33% +17.69% =========================================== Files 341 340 -1 Lines 14153 14141 -12 =========================================== + Hits 8865 11360 +2495 + Misses 5288 2781 -2507 ```

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