Rename svZeroDPlus to svZeroDSolver

[menon-karthik]

Current situation

Addresses #86 and #35. The move from StanfordCBCL to SimVascular involved renaming the repo to svZeroDSolver for consistency. The name therefore had to be updated in several places within the repo.

Release Notes

• Main change is the name being updated in the docs, cmake files, github actions, etc.
• Another important change is the renaming of the python interface. It used to be called svzerodplus. Since the name svzerodsolver is already taken by the main executable, I thought it would be a good idea to rename the python interface pysvzerod. Please let me know what you think @richterjakob!

Documentation

This PR mostly updates the docs. No code changes.

Testing

Github actions are passing.

Code of Conduct & Contributing Guidelines

• I agree to follow the Code of Conduct and Contributing Guidelines.

[menon-karthik]

@richterjakob I requested your review because I might have broken some things in the python interface and docker container while renaming things. I'm not sure if I did, because the tests are passing but I'm assuming the testing doesn't include the docker container. Please don't feel like you need to spend too much time on this, but just wanted to make sure those two things are working!

[menon-karthik]

@mrp089 Thanks for approving! I'll wait for @richterjakob to look at it whenever he gets a chance before merging (no hurry).

[mrp089]

Merging, as @richterjakob and I want to use the new name in https://github.com/StanfordCBCL/svSuperEstimator. He accepts the name changes with a tear in his eye.