Added support for custom OpenSSL selection

[toxicteddy00077]

Closes #5614

Added support for choosing custom OpenSSL version with three prospective methods:

1. Use submodule
2. Use OPENSSL_LIB_DIR and OPENSSL_INCLUDE_DIR variables
3. Use find_package

I mostly built on the suggestion given by the issue author

[toxicteddy00077]

@microsoft-github-policy-service agree

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 85.68%. Comparing base (3f1d8ec) to head (6da2ca2).
⚠️ Report is 22 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5799      +/-   ##
==========================================
- Coverage   86.34%   85.68%   -0.66%     
==========================================
  Files          60       60              
  Lines       18729    18732       +3     
==========================================
- Hits        16172    16051     -121     
- Misses       2557     2681     +124     

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[guhetier]

Thanks for the PR.
I don't think we can use the find_package approach with QuicTLS.

Our longer term goal is to stop depending on QuicTLS completely (once OpenSSL 3.5 is broadly available), so we could also add these new build config work only for openssl, not quictls.

[masa-koz]

@toxicteddy00077 Hi, I found a missing entry for Win32 in submodules/CMakeLists.txt.

--- a/submodules/CMakeLists.txt
+++ b/submodules/CMakeLists.txt
@@ -165,6 +165,7 @@ if (WIN32)
     )

     add_library(OpenSSLQuic::OpenSSLQuic ALIAS OpenSSLQuic)
+    add_library(OpenSSL::MsQuic ALIAS OpenSSLQuic)

[toxicteddy00077]

Thanks @masa-koz good catch, @guhetier please check now

[guhetier]

Sorry for the delay. One last thing I caught on the last check.
We should probably update our requirements, but in the meantime, and especially since this targets Linux, we should be compatible.