open-source-silicon.dev

<https://github.com/IHP-GmbH/IHP-Open-PDK/pull/353|#353 Update on Verilog-A models and compilation scripts>
Pull request opened by <https://github.com/KrzysztofHerman|KrzysztofHerman>
1. ngspice binaries placed in `$PDK_ROOT/$PDK/libs.tech/ngspice/osdi/`
2. Since `discipline.h` is not used it got removed
3. `.spiceinit` updated with the new location of the OSDI files
4. `$PDK_ROOT/$PDK/libs.tech/verilog-a/README.md` updated
<https://github.com/IHP-GmbH/IHP-Open-PDK|IHP-GmbH/IHP-Open-PDK>

<https://github.com/IHP-GmbH/IHP-Open-PDK/pull/353|#353 Update on Verilog-A models and compilation scripts>
Pull request merged by <https://github.com/sergeiandreyev|sergeiandreyev>
<https://github.com/IHP-GmbH/IHP-Open-PDK|IHP-GmbH/IHP-Open-PDK>