Added support for updated Reserved IP behavior to existing resources (instance, network_ips)

[AniJ98]

📝 Description

This PR implements functionality and tests for managing Reserved IP addresses in the Linodego client. These changes align with the updated Linode API, providing comprehensive support for Reserved IP operations. The changes include:

Implementation of core operations:

• Deleting a Linode while retaining the Reserved IP
• Retrieving IP information for Linodes, including Reserved IPs
• Listing all IP addresses, including Reserved IPs
• Allocating and assigning new Reserved IP addresses
• Assigning Reserved IPs to Linodes
• Fetching particular IP address, including Reserved IPs
• Converting between Ephemeral and Reserved IPs

Test coverage:

• TestInstance_DeleteInstanceVariants: Verifies Reserved IP retention after Linode deletion
• TestReservedIPAddresses_GetIPReservationStatus: Tests retrieval of Linode IP information including Reserved IPs
• TestIPAddresses_List_smoke: Checks filtering of all IPs by the reserved field.
• TestIPAddress_Instance_Allocate: Covers various scenarios for allocating Reserved IPs
• TestIPAddress_Instance_ReserveIP_Assign: Tests assigning Reserved IPs to Linodes
• TestIPAddress_GetFound: Tests fetching information about a particular IP address, including Reseved IPs
• TestIPAddress_Update: Verifies conversion between Ephemeral and Reserved IPs

✔️ How to Test

What are the steps to reproduce the issue or verify the changes?

1. Ensure you have a valid Linode API token.
Set up your environment:


export LINODE_TOKEN="your_token_here"

Additionally you need to set the following if you want to test it in a different environment:

export LINODE_URL="https://api.linode.com
export LINODE_API_VERSION="v4beta"

2. Navigate to the test directory within the linodego project.
Update the LINODE_TOKEN in the Makefile:

LINODE_TOKEN="your_token_here"

Run the tests using one of the following commands:
To run all integration tests:

make testint

To run a specific test:

go test -v ./integration -run TestInstance_DeleteInstanceVariants

3. Verify the test output for any failures or unexpected behavior.

Note:
Ensure that you have enough quota to reserve IP before adding it to an existing linode. Ensure the IPMAX limit is enough to allocate/ assign a reserved IP to a linode.