Python bindings

[auto-differentiation-dev]

Description

This adds Python bindings to XAD using pybind11, with the most essential functionality:

• first order forward and adjoint mode
• all math functions

Fixes #84

Type of change

• New feature (non-breaking change which adds functionality)
• This change requires a documentation update

[coveralls]

coverage: 98.79% (+0.2%) from 98.56%
when pulling 4dd6513 on feature/python-bindings
into f8eb1b2 on main.

[github-actions]

Test Results

    29 files  ± 0      29 suites  ±0   10m 45s ⏱️ -9s
 1 273 tests + 2   1 273 ✅ + 2  0 💤 ±0  0 ❌ ±0 
36 879 runs  +20  36 879 ✅ +20  0 💤 ±0  0 ❌ ±0 

Results for commit 4dd6513. ± Comparison against base commit f8eb1b2.

♻️ This comment has been updated with latest results.