Fix code scanning alert no. 83: Request without certificate validation

[vktrrdk]

Fixes https://github.com/deNBI/simplevm-client/security/code-scanning/83

To fix the problem, we need to ensure that SSL certificate verification is enabled for all HTTP requests. This can be done by removing the verify=False parameter or setting it to True. If a custom certificate is required, the path to the certificate should be provided.

1. Remove the verify=False parameter from the requests.get, requests.post, and requests.delete calls.
2. If necessary, add a parameter to the class to accept a custom certificate path and use it in the verify parameter.

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[github-actions]

Coverage Report

File	Stmts	Miss	Cover	Missing
simple_vm_client
VirtualMachineHandler.py	189	12	12	94%
__init__.py	1	0	100%
test_virtualmachinehandler.py	300	2	2	99%
simple_vm_client/benchmark
__init__.py	0	0	100%
test_service.py	52	36	36	31%
simple_vm_client/bibigrid_connector
__init__.py	0	0	100%
bibigrid_connector.py	118	5	5	96%
test_bibigrid_connector.py	173	0	100%
simple_vm_client/forc_connector
__init__.py	0	0	100%
forc_connector.py	255	4	4	98%
simple_vm_client/forc_connector/playbook
__init__.py	0	0	100%
playbook.py	190	0	100%
test_playbook.py	380	0	100%
simple_vm_client/forc_connector/template
__init__.py	0	0	100%
template.py	195	1	1	99%
simple_vm_client/metadata_connector
metadata_connector.py	88	71	71	19%
simple_vm_client/openstack_connector
__init__.py	0	0	100%
openstack_connector.py	900	118	118	87%
simple_vm_client/util
__init__.py	0	0	100%
state_enums.py	69	0	100%
test_thrift_converter.py	170	0	100%
thrift_converter.py	77	13	13	83%
TOTAL	3157	262	92%

Tests	Skipped	Failures	Errors	Time
300	0 💤	10 ❌	0 🔥	5.886s ⏱️