OpenVPN 2.5.5

What's new in this version:

User-visible Changes:
- SWEET32/64bit cipher deprecation change was postponed to 2.7
- Windows: use network address for emulated DHCP server as default this enables use of a /30 subnet, which is needed when connecting to OpenVPN Cloud.
- require EC support in windows builds (this means it's no longer possible to build a Windows OpenVPN binary with an OpenSSL lib without EC support)

New features:
- Windows build: use CFG and Spectre mitigations on MSVC builds
- bring back OpenSSL config loading to Windows builds. OpenSSL config is loaded from %installdir%SSLopenssl.cfg (typically: c:program filesopenvpnSSLopenssl.cfg) if it exists.
- This is important for some hardware tokens which need special OpenSSL config for correct operation. Trac #1296

Fixed:
- Windows build: enable EKM
- Windows build: improve various vcpkg related build issues
- Windows build: fix regression related to non-writeable status files (Trac #1430)
- Windows build: fix regression that broke OpenSSL EC support
- Windows build: fix "product version" display (2.5..4 -> 2.5.4)
- Windows build: fix regression preventing use of PKCS12 files
- improve "make check" to notice if "openvpn --show-cipher" crashes
- improve argv unit tests
- ensure unit tests work with mbedTLS builds without BF-CBC ciphers
- include "--push-remove" in the output of "openvpn --help"
- fix error in iptables syntax in example firewall.sh script
- fix "resolvconf -p" invocation in example "up" script
- fix "common_name" environment for script calls when "--username-as-common-name" is in effect (Trac #1434)

Documentation:
- move "push-peer-info" documentation from "server options" to "client" (where it belongs)
- correct "foreign_option_{n}" typo in manpage
- update IRC information in CONTRIBUTING.rst (libera.chat)
- README.down-root: fix plugin module name