new(rules): Change namespace privileges via unshare

[incertum]

What type of PR is this?

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

/kind feature

/kind bug

/kind cleanup

/kind design

/kind documentation

/kind failing-test

Any specific area of the project related to this PR?

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

/area rules

/area registry

/area build

/area documentation

Proposed rule maturity level

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/area maturity-stable

/area maturity-incubating

/area maturity-sandbox

/area maturity-deprecated

What this PR does / why we need it:

See desc and also part of modernizing Falco rules https://github.com/falcosecurity/rules/issues/138. CC @darryk10 @Andreagit97

Which issue(s) this PR fixes:

Fixes #

Special notes for your reviewer:

[poiana]

LGTM label has been added.

Git tree hash: ef0995f4d1b4bd7b063eb004cf93dc9db15d8e95

[poiana]

LGTM label has been added.

Git tree hash: c0668328313504ba333a829e9f32d51aa22679d5

[poiana]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: Andreagit97, darryk10, incertum

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Needs approval from an approver in each of these files: - ~~[OWNERS](https://github.com/falcosecurity/rules/blob/main/OWNERS)~~ [Andreagit97,incertum] Approvers can indicate their approval by writing `/approve` in a comment Approvers can cancel approval by writing `/approve cancel` in a comment

[Andreagit97]

/hold Why the CI is failing?

[incertum]

Because the memfd + exec rule made it already incompatible with 0.35.

[Andreagit97]

got it thanks! /unhold