Support for GETQUOTA and GETQUOTAROOT

[Sn0wCrack]

Similar to the imap_get_quota and imap_get_quotaroot functions in ext-imap.

[stevebauman]

Hey @Sn0wCrack, I can definitely get these added 👍

[Sn0wCrack]

I've actually had a bit of a crack at this myself.

Annoyingly the GreenMail program you use for testing does not properly support quotas from what I can tell.

I've left a comment for them upstream: greenmail-mail-test/greenmail#901

For my testing I've just used a personal mailbox I have.

I've opened a draft PR for it here: #107

[stevebauman]

Hey @Sn0wCrack, thanks for the PR! That's okay if it doesn't support it. I think it's fine if we use a unit test instead and supply an expected response that an IMAP server would send if they did actually support it 👍

[Sn0wCrack]

I've updated the PR now to include a unit test for the PR now and fixed up the array shape on the return to be the correct value.

[stevebauman]

Completed in #107. Thanks @Sn0wCrack 🙏