Implement some classes in Sisimai::Rhost::*

[azumakuniyuki]

• Consolidate error messages scattered under Sisimai::Reason::* into Sisimai::Rhost::* classes for each email service
• Sisimai::Rhost::YahooInc for https://senders.yahooinc.com/smtp-error-codes/
  • The following sample emails in set-of-emails/maildir/bsd:
  • rhost-yahooinc-01.eml
  • rhost-yahooinc-02.eml
  • rhost-yaoooinc-03.eml
• Sisimai::Rhost::Apple for iCloud Mail
  • The following sample emails in set-of-emails/maildir/bsd:
  • rhost-apple-01.eml
  • rhost-apple-02.eml
  • rhost-apple-03.eml
  • rhost-apple-04.eml

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 85.60%. Comparing base (ec9885c) to head (d251407).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## 5-stable #523 +/- ## ============================================ + Coverage 85.54% 85.60% +0.06% ============================================ Files 132 134 +2 Lines 6570 6599 +29 Branches 1937 1942 +5 ============================================ + Hits 5620 5649 +29 Misses 301 301 Partials 649 649 ```

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