Upgrade to IMDSv2 from v1 when calling EC2 Instance Metadata.

[mirelap-amazon]

Issue #, if available:

Description of changes:

Testing:
I tested one unit test on a specific host and here are the logs:

pytest -vv -o log_cli=true test/unit/agent_metadata/test_aws_ec2_instance.py

DEBUG    codeguru_profiler_agent.agent_metadata.fleet_info:fleet_info.py:20 Making a request to http://169.254.169.254/latest/api/token with headers set for these keys: dict_keys(['X-aws-ec2-metadata-token-ttl-seconds'])
DEBUG    codeguru_profiler_agent.agent_metadata.fleet_info:fleet_info.py:20 Making a request to http://169.254.169.254/latest/meta-data/local-hostname with headers set for these keys: dict_keys(['X-aws-ec2-metadata-token'])
DEBUG    codeguru_profiler_agent.agent_metadata.fleet_info:fleet_info.py:20 Making a request to http://169.254.169.254/latest/meta-data/instance-type with headers set for these keys: dict_keys(['X-aws-ec2-metadata-token'])
PASSED                                                                                                             [ 33%]
test/unit/agent_metadata/test_aws_ec2_instance.py::TestAWSEC2Instance::TestLookUpMetadata::TestWhenHostNameCannotBeDetermined::test_it_returns_none 

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[PapaPedro]

not sure you need to provide a real token here, it may trigger some security scripts that search the code for those. Could you just put a fake string here?

[mirelap-amazon]

It's not real, it's based on a real one, but then I updates random characters from it.

[mirelap-amazon]

But I agree it still can trigger some security scripts, I will update.

[mirelap-amazon]

Just updated it, thanks.

[PapaPedro]

if we call both __look_up_instance_type and __look_up_host_name successively, we are going to get 2 different tokens, can you maybe update the look_up_metadata function to get a token once and reuse it?

[mirelap-amazon]

Okay, updated; thanks!