Update implementation.py to check for .exploded attribute

[palmersample]

When generating dynamic testbed objects, implementation.py expects an ipaddress object to be passed as the IP address. This change checks for the existence of the exploded attribute for each IP / host before assigning that attribute, simplifying dynamic testbed creation using string values for addresses

In addition, the IOS XE implementation has been updated to properly generate an IPv6 URL in the format [xxxx:yyyy....]:{port} to validate functionality. If this passes scrutiny and code style checks, another PR will be generated to update other implementations.

[dwapstra]

To use an address that is not an IPAddress object, you can pass the host key instead.

For this change I suggest the following code:

ip = self.connection_info['ip']
if isinstance(ip, (ipaddress.IPv4Address, ipaddress.IPv6Address)):
   ip = ip.exploded

[palmersample]

Minor changes to proposed solution (for your review):

1. Reduce scope of imports - only ip_address, IPv4Address, and IPv6Address from the ipaddress package.
2. IP logic to check if the ip is NOT an instance of IPv4 or IPv6 - if this is true, generate a new ip_address object. This allows testing of IPv6Address and subsequent URL fixup.

Example change from IOS XE follows:

            ip = self.connection_info['ip']
            if not isinstance(ip, (IPv4Address, IPv6Address)):
                ip = ip_address(ip)

            # Properly format IPv6 URL if a v6 address is provided
            if isinstance(ip, IPv6Address):
                ip = f"[{ip.exploded}]"
            else:
                ip = ip.exploded