feat: add support for custom CIDR ingress/egress rules (#60)

- Added `additional_allowed_cidr_ingress` and `additional_allowed_cidr_egress` fields to `TenantNetworkPolicy` to allow specifying custom CIDR blocks for network access.
- Updated K8sTenantManager to parse and apply these CIDR rules to NetworkPolicy ingress and egress rules.
- Added `cidr` dependency to `harmony_macros` and a custom proc macro `cidrv4` to easily parse CIDR strings.
- Updated TenantConfig to default inter tenant and internet egress to deny all and added default empty vectors for CIDR ingress and egress.
- Updated ResourceLimits to implement default.

Reviewed-on: #60
Co-authored-by: Jean-Gabriel Gill-Couture <jg@nationtech.io>
Co-committed-by: Jean-Gabriel Gill-Couture <jg@nationtech.io>

Cargo.toml

@@ -24,7 +24,7 @@ env_logger = "0.11.5"
 derive-new = "0.7.0"
 async-trait = "0.1.82"
 tokio = { version = "1.40.0", features = ["io-std", "fs", "macros", "rt-multi-thread"] }
-cidr = "0.2.3"
+cidr = { features = ["serde"], version = "0.2" }
 russh = "0.45.0"
 russh-keys = "0.45.0"
 rand = "0.8.5"