doc: convert standard project docs to markdown

In the first step, we just add the .md extension and move some
files around, without changing any content. These changes will
occur in the following commits.

Reviewed-by: Tomas Mraz <tmraz@fedoraproject.org>
(Merged from https://github.com/openssl/openssl/pull/10545)

diff --git a/ACKNOWLEDGEMENTS b/ACKNOWLEDGEMENTS.md
similarity index 100%
rename from ACKNOWLEDGEMENTS
rename to ACKNOWLEDGEMENTS.md

diff --git a/AUTHORS b/AUTHORS.md
similarity index 100%
rename from AUTHORS
rename to AUTHORS.md

diff --git a/CHANGES b/CHANGES.md
similarity index 100%
rename from CHANGES
rename to CHANGES.md

diff --git a/CONTRIBUTING b/CONTRIBUTING.md
similarity index 100%
rename from CONTRIBUTING
rename to CONTRIBUTING.md

diff --git a/FAQ b/FAQ.md
similarity index 100%
rename from FAQ
rename to FAQ.md

diff --git a/INSTALL b/INSTALL.md
similarity index 100%
rename from INSTALL
rename to INSTALL.md

diff --git a/NEWS b/NEWS.md
similarity index 100%
rename from NEWS
rename to NEWS.md

diff --git a/README b/README.md
similarity index 100%
rename from README
rename to README.md

diff --git a/.github/SUPPORT.md b/SUPPORT.md
similarity index 100%
rename from .github/SUPPORT.md
rename to SUPPORT.md