Add support for Email routing

[Cyb3r-Jak3]

Description

Adds support for the email routing APIs
https://api.cloudflare.com/#email-routing---destination-addresses-properties
https://api.cloudflare.com/#email-routing---routing-rules-properties
https://api.cloudflare.com/#email-routing---settings-properties

Has your change been tested?

Unit tests added and all unit tests pass

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 (api.cloudflare.com or developers.cloudflare.com) and stable APIs.

[github-actions]

changelog detected ✅

[codecov-commenter]

Codecov Report

Merging #1034 (5d89260) into master (6c5ea4a) will increase coverage by 0.66%.
The diff coverage is 64.08%.

@@            Coverage Diff             @@
##           master    #1034      +/-   ##
==========================================
+ Coverage   49.06%   49.72%   +0.66%     
==========================================
  Files         108      115       +7     
  Lines       10428    10850     +422     
==========================================
+ Hits         5116     5395     +279     
- Misses       4200     4295      +95     
- Partials     1112     1160      +48     

Impacted Files	Coverage Δ
access_application.go	76.52% <ø> (ø)
access_bookmark.go	72.44% <ø> (ø)
workers_account_settings.go	35.71% <35.71%> (ø)
workers_tail.go	52.00% <52.00%> (ø)
workers_subdomain.go	57.14% <57.14%> (ø)
email_routing_settings.go	60.00% <60.00%> (ø)
email_routing_rules.go	65.64% <65.64%> (ø)
email_routing_destination.go	66.25% <66.25%> (ø)
filter.go	42.96% <72.72%> (+0.51%)	⬆️
firewall_rules.go	53.98% <75.75%> (+1.39%)	⬆️
... and 6 more

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[jacobbednarz]

[github-actions]

This functionality has been released in v0.47.0.

For further feature requests or bug reports with this functionality, please create a new GitHub issue following the template. Thank you!