Migrate populating local demo data through database.sql to using NetBox API

[henrybear327]

Several changes are introduced in this PR

• database.sql is stripped down to only populating the API token
• The local demo data is now populated through NetBox API, by using a Python script and running as a Kubernetes job, which makes it easier to work across NetBox versions. (idea from @jstudler)

e2e tests are modified accordingly, as we also migrate to using locally-created tenants and sites only (idea from @bruelea ). We are also check if the tenant and site from parentPrefixSelector and the spec is properly leveraged by using 2 different tenants and sites.

Implements and closes #175

[henrybear327]

There are several TODO(henrybear327) that will be deferred for the future, as it's NetBox implementation-related issues

[henrybear327]

To run the e2e test locally, please use a clean kind cluster (you can remove the current one by executing kind delete cluster --name kind), and execute make create-kind deploy-kind test-e2e @faebr

[faebr]

Looks way clearer now with the python script I like it. Also tested it locally on my machine and works as expected.