Adds snippet support

[joshuamsager]

Description

Adds snippet support to the API

I wasn't sure how far away v2/v3 will land and my team would love to have Snippets supported in Terraform. If this is accepted, I can work on getting the Snippet rules next.

Adds:

• GetSnippet
• ListSnippets
• DeleteSnippet
• PutSnippet

I still have some further testing to do to make sure that these all behave as expected.

Types of changes

What sort of change does your code introduce/modify?

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have added tests to cover my changes.
• All new and existing tests passed.
• This change is using publicly documented in cloudflare/api-schemas
  and relies on stable APIs.

[jacobbednarz]

v2/v3 already has this support so unless you need something specifically in the v0 range, i would recommend using it instead of adding this.

we already support the newer library in the terraform provider as well.