#451: model and types

[filippomc]

Closes #451

Implemented solution: model stubs have been added based on OpenApi specification, and these models have been used to refactor the relevant apis to include typing hints.
The solution is backwards compatible as the new models can be used with the dictionary api as well.

How to test this PR:
Most of the new functionality is test covered to be backwards compatible. Functionality based on the cloudharness Python library should work untouched if developed following the main develoment templates. The main functionality that may be affected is data serialization/deserialization.

Even if everything has been done to make this backwards compatible, it's a quite of a radical change so additional attention is needed on deployments.
The main change is the new dependency introduced on the cloudharness_models library: the installation process of cloudharness has been improved to accommodate the new library (and other future library additions).

• Codefresh deployment files need to be regenerated as the cloudharness installation is changed
• The new dependency may break Docker images depending on the Cloudharness Python library

Sanity checks:

• The pull request is explicitly linked to the relevant issue(s)
• The issue is well described: clearly states the problem and the general proposed solution(s)
• From the issue and the current PR it is explicitly stated how to test the current change
• The labels in the issue set the scope and the type of issue (bug, feature, etc.)
• All the automated test checks are passing
• All the linked issues are included in one milestone
• All the linked issues are in the Review/QA column of the board
• All the linked issues are assigned

Breaking changes (select one):

• The present changes do not change the preexisting api in any way
• This PR and the issue are tagged as a breaking-change

Possible deployment updates issues (select one):

• There is no reason why deployments based on CloudHarness may break after the current update
• This PR and the issue are tagged as alert:deployment

Test coverage (select one):

• Tests for the relevant cases are included in this pr
• The changes included in this pr are out of the current test coverage scope

Documentation (select one):

• The documentation has been updated to match the current changes
• The changes included in this PR are out of the current documentation scope

Nice to have (if relevant):

• Screenshots of the changes
• Explanatory video/animated gif