Examine and port remaining polynomial code from scmutils/poly

[sritchie]

SOME of this exists in the polynomial namespaces I have already, but it is scattered. Here is what currently exists: https://github.com/sicmutils/sicmutils/tree/main/src/sicmutils/polynomial

There will be good stuff here!

• [ ] hermite.scm
• [ ] interp-generic.scm
• [ ] interp.scm
• [ ] lagrange.scm
• [ ] legendre.scm
• [ ] nchebpoly.scm
• [ ] polyinterp.scm
• [ ] polyroot.scm
• [ ] ppa.scm