Bring Nanobind. Fix object leak in from_numpy

[ferdonline]

Context

Neuron Python bindings have been implemented by using the Python C API directly. Among the major issues we identified:

• ref-counting, which is simply too easy to get wrong, especially for routines that can exit early.
• Identifying which references should be borrowed or stollen, which requires a careful read of the API and reference management.
• The API verbosity. Operations like looping over a Python list are verbose, error prone and not particularly intuitive, incurring a high maintenance toll.

Such problems lead to "undead" objects i.e., objects which are no longer in use but due to its wrong ref count they are not garbage collected, keep using valuable memory.

This PR

In this PR we bring nanobind to improve our lives and apply it to solve a case where there was such leaking of undead objects.

TODO

• Find a way to avoid git update --recursive as this is only needed for nanobind
• Try to expose symbols on windows without using dllexport or do it in a separate header file.

[azure-pipelines]

✔️ 07d58f6 -> Azure artifacts URL

[azure-pipelines]

✔️ bf98304 -> Azure artifacts URL

[azure-pipelines]

✔️ 05ed787 -> Azure artifacts URL

[azure-pipelines]

✔️ f84830b -> Azure artifacts URL

[alkino]

And so we use NRN_EXPORT on all functions, because gcc has no flag, to change the visibility for all functions.
cmake has one but seems broken with gcc compilation for windows: https://discourse.cmake.org/t/too-restrictive-for-coff-obj-files-in-create-def/11077

[alkino]

For the git and recursivity I have no idea how to do it better.

[pramodk]

Just one minor comment for clarifications otherwise LGTM!

@ramcdougal has already given a green signal last month.

@nrnhines: you approved this last year. In case you want to take a look again, let us know. Otherwise I think this is ready to go!

thanks a lot @alkino ! 🎉 (& @ferdonline 🍾)

[azure-pipelines]

✔️ 28bf8ef -> Azure artifacts URL

[azure-pipelines]

✔️ c218b71 -> Azure artifacts URL

[sonarcloud]

Quality Gate passed

Issues
22 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarCloud

[azure-pipelines]

✔️ ae200cc -> Azure artifacts URL

[bbpbuildbot]

Logfiles from GitLab pipeline #219008 (:no_entry:) have been uploaded here!

Status and direct links:

• ✅ mac_m1_cmake_build: [cmake, ON, OFF, OFF, address]
• ✅ spack_setup
• ✅ build:nmodl
• ✅ build:neuron:nmodl:intel:legacy
• ✅ build:neuron:nmodl:intel:shared
• ✅ build:neuron:nmodl:nvhpc:acc:legacy
• ✅ build:neuron:nmodl:nvhpc:acc:shared
• ✅ build:neuron:nmodl:nvhpc:omp:legacy
• ✅ build:neuron:nmodl:nvhpc:omp
• ✅ test:neuron:nmodl:intel:legacy
• ✅ test:neuron:nmodl:intel:shared
• ⛔ test:neuron:nmodl:nvhpc:acc:legacy
• ✅ test:neuron:nmodl:nvhpc:acc:shared
• ✅ test:neuron:nmodl:nvhpc:omp:legacy
• ✅ test:neuron:nmodl:nvhpc:omp