Support to skip device type updates

[mzbroch]

This PR adds a capability of skipping the device type updates for existing NetBox devices in case of re-onboarding process. This is also a re-iteration for the previous MR !74

New plugin settings :

• skip_device_type_on_update
• skip_manufacturer_on_update

[glennmatthews]

We could really stand to have some more test automation for this plugin. This PR brings us to 14 separate configurable settings, and it's not obvious to me whether these 2 new ones coexist with the previously existing 12 in all relevant permutations.

Also, why only skip_device_type_on_update and skip_manufacturer_on_update? Are we going to see a separate feature request for skip_platform_on_update, skip_device_role_on_update, and/or skip_management_interface_on_update in the future?

[dgarros]

@glennmatthews fair point. To answer your question, yes we should add similar parameters to allow the user to exclude/skip the other attributes of a device that will be update when we are re-onboarding a device in the future. We did these 2 in priority to bring the develop-2.0 branch at feature parity with the 1.3 release in prevision of a 2.0 release.

Considering the growing number of questions regarding the support for NetBox 2.9, @mzbroch suggested that we ship the 2.0 release once this PR has been merged and target a 2.1 release in the near future to improve the test coverage and add couple of features we wanted to get in 2.0 initially (metrics, support for interfaces etc..). Does this plan works for you ?

[glennmatthews]

Sounds like a good plan to me.

[mzbroch]

@glennmatthews @dgarros Indeed, there are many potential permutations of introducing multiple new settings for every scenario. Device Type and Manufacturer are the ones that users tend to apply a different value to describe the same vendor / hardware element - thus an option in the plugin allows users for more customizable plugin behaviour.

I consider this PR complementary to the @dgarros 's PR #77 and issue #79