feat: VM staticIP: add network-mapping ConfigMap parsing and IP translation for VM static-IP DR

Background / Motivation
-----------------------
This work is part of the VM static-IP DR solution for UDN/CUDN-based
networking and is intended to support the KubeVirt design:

  "Requesting a Specific IP for a VM in UDN via Third-Party Integration"

When a VM fails over or fails back between clusters, statically assigned
IPs may need translation to equivalent addresses on the peer cluster.

The translation framework introduced in this PR is generic, but its
primary motivating use case is VM static IPs provisioned through
UDN/CUDN integrations.

Translation scope is NAD-based
------------------------------
The implementation scopes translation rules using:

  networkRef:
    nadNamespace:
    nadName:

rather than by IP alone.

This is intentional because:

- the same IP/subnet may legitimately exist in multiple UDNs
- translation must be network-scoped
- UDNs and CUDNs ultimately materialise as NADs consumed by VMs

The implementation therefore works for:

- NADs created directly by users
- NADs generated from UDNs
- NADs generated from CUDNs

without introducing separate schema concepts for each network type.

Supported translation mechanisms
--------------------------------
Three translation models are supported.

1. explicitMappings

  explicitMappings:
  - dr1: 192.168.100.51
    dr2: 192.168.110.58

Use case:

  one-to-one VM IP remapping

Priority:

  highest

Lookup:

  O(1)

via pre-built forward/reverse maps.

2. cidr

  cidr:
    dr1: 192.168.100.0/24
    dr2: 192.168.110.0/24

Use case:

  subnet-preserving host translation

Example:

  192.168.100.25 → 192.168.110.25

Requirements:

- same address family
- same prefix length
- source and destination networks must differ

3. regexMappings

  regexMappings:
    dr1-to-dr2:
      ...
    dr2-to-dr1:
      ...

Use case:

  arbitrary/non-symmetric translations

Direction is explicit because regex transformations are not inherently
reversible.

Deterministic direction model
-----------------------------
Direction is not inferred from the IP address.

Instead:

  TranslateIP(srcIP, sourceCluster, ...)

uses the caller-supplied source cluster name.

Benefits:

- avoids ambiguity with overlapping subnets
- avoids ambiguity with regex mappings
- keeps failover/failback behaviour deterministic

Evaluation order
----------------
Translation is applied in the following order:

  explicitMappings
      ↓
  cidr
      ↓
  regexMappings

This ensures:

- specific VM overrides win
- subnet translations act as defaults
- regex rules act as a fallback

Validation guarantees
---------------------
The parser performs strict validation before rules become active.

CIDR

Validates:

- cluster keys present
- valid CIDR syntax
- equal prefix lengths
- source network != destination network

explicitMappings

Validates:

- IPv4-only
- cluster keys present
- no duplicate source IPs
- no duplicate destination IPs
- no cross-column ambiguity
- source IP != destination IP

regexMappings

Validates:

- both directions present
- valid regex syntax
- non-empty pattern/replacement

Operational behaviour
---------------------
Configuration errors do not block DR workflows.

If:

- ConfigMap missing
- ConfigMap invalid
- Translation fails

then:

  ConditionNetworkMappingLoaded=False

is reported and:

  translateSourceIP()

returns the original IP unchanged.

This preserves DR orchestration while surfacing configuration problems.

Non-goals of this PR
--------------------
Not included:

- ConfigMap watch/reload
- DRPolicy integration for ConfigMap reference
- Discovery of VM static IPs
- Cloud-Init parsing
- UDN/CUDN network discovery

This PR is intentionally limited to:

- ConfigMap parsing
- Validation
- Translation engine
- Runtime translation APIs

Design rationale
----------------
The most important design decision is:

  Translation is scoped by network identity (NAD) rather than by IP
  address.

This avoids ambiguity in environments where:

- multiple UDNs use overlapping subnets
- the same IP may exist on different networks
- CUDN/UDN-generated NADs coexist with user-created NADs

Assisted by: IBM Bob v2.0.2

Signed-off-by: pruthvitd <prd@redhat.com>

Author: pruthvitd

api/v1alpha1/drplacementcontrol_types.go

@@ -80,6 +80,11 @@ const (
 	// GlobalActionConsensus condition indicates whether all DRPCs sharing the same global VGR label
 	// agree on the DR action and target cluster.
 	ConditionGlobalAction = "GlobalAction"
+
+	// NetworkMappingLoaded condition indicates whether the network-mapping ConfigMap referenced
+	// by the drplacementcontrol.ramendr.openshift.io/network-mapping annotation was successfully
+	// loaded. False means IP translation is disabled for this DRPC; DR orchestration continues.
+	ConditionNetworkMappingLoaded = "NetworkMappingLoaded"
 )
 
 const (