feat(decl): add declarative test framework foundation

[ekoops]

What type of PR is this?

Uncomment one (or more) /kind <> lines:

/kind bug

/kind cleanup

/kind documentation

/kind tests

/kind feature

Any specific area of the project related to this PR?

Uncomment one (or more) /area <> lines:

/area commands

/area pkg

/area events

What this PR does / why we need it: This PR provides the foundation to develop a completely declarative test framework. It introduces the following addition:

• a loader (implemented in the pkg/test/loader package) to load YAML tests configurations
• the notion of test step (pkg/test/step) and field binding A test is made of multiple test steps. A test step has two mandatory fields: type and name. The type is used to identify the kind of step the user wants to run and the remaining set of parameters the user must provide in order to run it. The name is used to uniquely identify the step in order to let other test steps reference it in a subsequent "field binding", A field binding a field allows to reuse the value of a field of a preceding step. In a test YAML description, a field binding will look like this: dstField: ${stepName.srcField} .
• a generic way to reference and assign values to any test step field (see pkg/test/field package) This leverages reflection and struct field tagging to move around field values and check for semantic assignability. A source field is assignable to a destination field if the following two condition applies:
  • source field go type is assignable and/or convertible to destination field go type
  • source field is semantically assignable to destination field "Semantically assignable" means that both fields have the same field_type. A field_type is assigned to a field via struct field tagging.
• a generic way to implement a system call test step (pkg/test/step/syscall/base) This leverages reflection.
• implementation of system call test steps for the following system calls:
  • write
  • read
  • open
  • openat
  • openat2
  • symlink
  • symlinkat
  • link
  • linkat
  • init_module
  • finit_module
  • dup
  • dup2
  • dup3
  • connect
  • socket
  • sendto

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

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

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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)~~ [alacuku] 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: 80caa3b4078cbd51f325cdf58761057c59f23551