Init container changes for getting all the primary attached interfaces

[jaydeokar]

What type of PR is this?
feature

Which issue does this PR fix?:
N/A

What does this PR do / Why do we need it?:
This adds changes to Init container for CNI. When Multiple NICs are initialized, the init container will identify these interfaces to set kernel parameters.
We skip efa-only interfaces since these cannot be used for IP traffic

Testing done on this change:
Tested on single card instance and multi-card instance

time="2025-02-28T07:26:45Z" level=info msg="Copying CNI plugin binaries ..."
time="2025-02-28T07:26:45Z" level=info msg="Copied all CNI plugin binaries to /host/opt/cni/bin"
time="2025-02-28T07:26:45Z" level=info msg="found primary interfaces for the host [eth0]"
time="2025-02-28T07:26:45Z" level=info msg="Found primaryIF [eth0]"
time="2025-02-28T07:26:45Z" level=info msg="Updated net/ipv4/conf/eth0/rp_filter to 2\n"
time="2025-02-28T07:26:45Z" level=info msg="Updated net/ipv4/tcp_early_demux to 1\n"
time="2025-02-28T07:26:45Z" level=info msg="CNI init container done"

Will this PR introduce any new dependencies?:
No new dependencies.. We already made IMDS calls. But we do have a bit more IMDS calls than previous

Will this break upgrades or downgrades? Has updating a running cluster been tested?:
No, should not break upgrade or downgrade..

Does this change require updates to the CNI daemonset config files to work?:
No

Does this PR introduce any user-facing change?:
Not with this change

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[jayanthvn]

Won't this return all ENIs - i.e, even secondary ENIs -

amazon-vpc-cni-k8s/pkg/awsutils/imds.go

Line 210 in 0dccb22

// GetMACs returns the interface addresses attached to the instance.

[jaydeokar]

Yes.. But we are filtering the ENIs which are attached to device-number 0..