issues/337: Fix DNS rebinding via http

[komuw]

• Previously if a malicious person sets bad.com to point to an IP that you own.

  curl -vkL https://bad.com
  curl: (35) OpenSSL/3.0.9: error:0A000438:SSL routines::tlsv1 alert internal error

  but,

  curl -vkL http://bad.com
  HTTP/1.1 308 Permanent Redirect
  Location: https://myGoodDomain.com/
  GET / HTTP/2
  Host: myGoodDomain.com
  HTTP/2 200

• This is because the redirector middleware first checked if a request is http and redirected it to https at the good domain, without first checking if the incoming Host header has the wrong value.

• This PR fixes that and we now first check that the Host header has the right value, before moving on to https redirection. This does not fix all the issues, but it should suffice. See the comment that was added in the code.

• Fixes: https://github.com/komuw/ong/issues/337

[codecov-commenter]

Codecov Report

Patch coverage: 100.00% and project coverage change: +0.09% :tada:

Comparison is base (a76d950) 74.87% compared to head (f3b6c96) 74.96%. Report is 2 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #338 +/- ## ========================================== + Coverage 74.87% 74.96% +0.09% ========================================== Files 44 44 Lines 4947 4965 +18 ========================================== + Hits 3704 3722 +18 Misses 995 995 Partials 248 248 ``` | [Files Changed](https://app.codecov.io/gh/komuw/ong/pull/338?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Komu+Wairagu) | Coverage Δ | | |---|---|---| | [middleware/redirect.go](https://app.codecov.io/gh/komuw/ong/pull/338?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Komu+Wairagu#diff-bWlkZGxld2FyZS9yZWRpcmVjdC5nbw==) | `91.58% <100.00%> (+1.37%)` | :arrow_up: | | [server/pprof.go](https://app.codecov.io/gh/komuw/ong/pull/338?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Komu+Wairagu#diff-c2VydmVyL3Bwcm9mLmdv) | `87.50% <100.00%> (-0.22%)` | :arrow_down: | | [server/server.go](https://app.codecov.io/gh/komuw/ong/pull/338?src=pr&el=tree&utm_medium=referral&utm_source=github&utm_content=comment&utm_campaign=pr+comments&utm_term=Komu+Wairagu#diff-c2VydmVyL3NlcnZlci5nbw==) | `75.90% <100.00%> (+0.39%)` | :arrow_up: |

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