feat(decl/resources): introduce test resource concept and clientServer resource

[ekoops]

What type of PR is this?

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/kind bug

/kind cleanup

/kind documentation

/kind tests

/kind feature

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/area commands

/area pkg

/area events

What this PR does / why we need it: This PR introduces the concept of test resource and the clientServer test resource.

A test resource abstracts a resource the user wants to use in a test, hiding the implementation details and letting the user focus only on the action that will trigger the Falco rule.

The clientServer test resource sets up a client and a server, and enables their communication by tuning the underlying network infrastructure. The user can specify udp4, udp6, tcp4, tcp6 or unix as transport protocol. For connection-oriented transport protocols, the client is automatically connected to the server. The resource enables field binding to both client and server information.

The PR also removes a print statement in the socket system call test step.

Which issue(s) this PR fixes:

Fixes #

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[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ekoops, FedeDP

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/falcosecurity/event-generator/blob/declarative-testing/OWNERS)~~ [FedeDP] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[poiana]

LGTM label has been added.

Git tree hash: 852acc82fa53d62747ab4d1503793bea8350ec12