chore: add diagnostics

[baszalmstra]

This PR adds the use of segvec::SegVec to allocate clauses. This reduces the number of very large allocations performed by the library.

I also added functionality to report diagnostics to make it easier to debug what is going on.

[wolfv]

Cool stuff! Did you benchmark that using segvec is beneficial?

The diagnostics are very nice.

[baszalmstra]

I have not, I will run a benchmark at the end of the day.

[baszalmstra]

But without it, I ran into issue with the solver trying to allocate 1.5GB in one go, which causes an OOM.

[baszalmstra]

These are the timings results:

There is no significant increase in outliers, but on average, the code became slightly slower.

Ill try removing the segvec later and try again to see if thats the issue.

[tdejager]

Now prints something like:

Total number of solvables:  4
Total number of watches:    6 (512 B)
Total number of variables:  4 (108 B)
Total number of clauses:    5 (160 B)
- Requires:                 1
- Constrains:               0
- Lock:                     0
- Learned:                  0
- ForbidMultiple:           2
  - opentelemetry-api:      2

Removed SegVec cause it seems slower.