ci: Attempt to cache build to speed up CI

[Jakuje]

No description provided.

[Jakuje]

This sounds like does the job now:

• The caches are created in https://github.com/latchset/kryoptic/actions/caches (~500MB for OpenSSL and ~100MB for Rust dependencies)
• The build time gets to ~1 minute from ~6 minutes previously

The ugly thing is that we need to write the openssl cache only from the fips build (which is usable also in the non-fips one).

[Jakuje]

Now, the most of the time takes the Fedora dependencies installation. This could be solved by creating a special build image, but lets postpone this, if this is going to work.

[simo5]

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