Bump up version requirement for CMake

[anderkve]

As discussed in Core meetings, I have now bumped up the CMake version requirement to CMake 3.16.3 (default in Ubuntu 20.04 LTS.) As part of that I also got rid of the FindSQLite3.cmake module, as this is now part of CMake.

I've tested that this works on my system, both running my default CMake (3.26.3) and the oldest allowed version (3.16.3), and both with and without finding SQLite3.

This is just a quick PR to check that the CI job still runs fine. I don't think this needs any further review.

[anderkve]

For some reason the HepLike backend ends up with status absent/broken on this branch, even though I can't see that any of the very few changes on this branch should impact HepLike in any way. This problem is the reason why the Ubuntu CI job fails, because the WC.yaml test run stops during dependecy resolution.

I've confirmed that I get the same absent/broken status for HepLike on my Ubuntu laptop when I'm on this branch, but I have yet to figure out why... (All the BOSS-generated library symbols seem to be present in the HepLike shared library.)

Any ideas, @tegonzalo or others?

[tegonzalo]

Interesting. Did you try running spartan? Turns out that the error that shows on the logs for heplike, which is the same as when running spartan, is our old friend undefined symbol: _ZTIN4YAML13BadConversionE. Why would this show just by upping the cmake version, beats me. Is it possible that the FindSQL file somehow overule some visibility stuff, so when removed this issue popped up?

[anderkve]

Some quick notes from the Core meeting minutes:

• The issue is not only with heplike -- also the old issue with scanner plugins came back
• Suggestion: unhide specific symbols: yaml-cpp, scanner plugins, etc
• Use make_symbols_visible function on specific cases

[tegonzalo]

Related to #492

[ChrisJChang]

From Core discussion: We should test whether we still see this problem, and if not, progress this PR.