Improve CAA record handling

[ptous]

This PR aims to address two issues I ran into attempting to create CAA records with the Provider. Feel free to use it as idea fodder rather than merging it directly. (See especially the 2nd bullet under "What I Changed" below.)

What I wanted to fix

• It seems that the issuing domain for CAA issue and issuewild records is wrapped in quotes by your back-end. For example, 0 issue amazon.com becomes 0 issue "amazon.com". (My conclusion that this happens is based creating the records in TF and then inspecting the records in the Namecheap web console.). However, because the provider allows the record without quotes, and stores it like that in TF state, such records forever shows a difference when planned, saying the record was removed outside of Terraform and needs to be created. (Edit: That behavior describes a MERGE mode operation.)
• CAA iodef records should permit a mailto: address, but the provider (or more accurately, the vendored go-namecheap-sdk library) checks that the record against a regex that only permits proto:// style addresses with two trailing slashes. There are no trailing slashes with the mailto: protocol.

What I changed

This PR contains what seemed like minimal changes needed to address these issues.

• I renamed fixCAAIodefAddressValue() to fixCAAAddressValue() and apply it to all CAA records, not just iodef types. This ensures the domain is always quoted, to match what your back-end actually creates.
• I modified the regex used in iodef URL protocol matches to make the // after the : optional. I realize this should really not be changed in a vendored copy of the go-namecheap-sdk, but I figured this was a simple way to show the change in context. Honestly, this regex (and the check in general) could stand to be made smarter. From what I can tell, only http://, https:// and mailto: are expected in an iodef CAA record, so the regex could be something like https?://|mailto:. And if you're going to check the protocol at all, you might want to check the whole URI for validity. For example, the current logic doesn't care what protocol name you put in front of the slashes or check that the rest of the URL is valid.
• I fixed a small spelling error / typo. hasSuffixQuite() -> hasSuffixQuote()
• I also tossed in a change you should feel free to ignore if it isn't valid or reasonable: the default ttl for records being 1799s seconds, or 29 minutes, 59 seconds. That just seemed strange, since even your web console offers standard values like 5, 10, 30 and 60 minutes. But you may have good reasons for using that value here. :man_shrugging:

Did I test this?

Yes. I modified the tests so go test will pass with the changes to fixCAAIodefAddressValue(). I also added new test cases for the expanded use.

Additionally, I tested the provider locally and verified the following:

• CAA issue and issuewild records that lack quotes around the domain now show no differences when you plan after apply. Note that Terraform thinks that records with and without quotes are different records, so changing them back and forth to quoted or not in HCL will cause plan differences between changes. However, entries are now consistent with your back-end behavior whether they have quotes in the HCL or not.
• I was able to create a CAA iodef records with a mailto: URI. where previously this would fail on apply.

[ptous]

The forced pushes were to add sign-off (for DCO) and then to fix the email on my commit to match the key I signed it with. :stuck_out_tongue:

[psa]

@alexvlasov Can this please be merged?