Basic support for account load balancers

[tpolich]

Description

Basic support for account level load balancers.

Has your change been tested?

Duplicated the existing zone tests and altered them for account based LB which are identical except they don't have a "name".

Screenshots (if appropriate):

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.
• [soon] This change is using publicly documented in cloudflare/api-schemas
  and relies on stable APIs.

[github-actions]

Oops! It looks like no changelog entry is attached to this PR. Please include a release note as described in https://github.com/cloudflare/cloudflare-go/blob/master/docs/changelog-process.md.

Example:

```release-note:TYPE
Release note
```

If you do not require a release note to be included, please add the workflow/skip-changelog-entry label.

[jacobbednarz]

as the CRUD method signatures already include the *ResourceContainer we can add a condition inside of those methods for the account level load balancers instead of using seperate new methods (we already have zone + user).

[tpolich]

the changelog check blows up on a go version mismatch but I've updated the functions to switch on the resource container level

[jacobbednarz]

updated the usage of the ResourceContainer to trim down one extra switch statement. let me know when this is ready with docs and we'll get it merged in.

i'll take a look at the changelog test failure but it looks correct for the usage here.

[tpolich]

oh that's a very nice improvement I didn't realize the constants actually were the text strings at the end of the day.