Sky130 - Convert to Pydantic, support sky130_scl

[harrisonliew]

• Implemented method gen_config for tech plugins to override and generate their own config (TechJSON instance, i.e. directly creating the Pydantic model). This enables multi-library support within the same tech plugin.
• Removed all existing sky130-tech-gen-... scripts and outputs, static sky130.tech.json
• Upstream @nayiri-k's tech LEF parsing of Metals into LEFUtils (unfortunately can't create Metal object directly or else it has a circular import)
• Fixed gds_map_file reading in OpenROAD plugin
• Adds more robust tech overriding (automatically uses cache paths for PDK collateral if they exist, and allows for manually hacked paths through technology.override_libraries: [] and technology.manually_override_pdk_collateral: bool

TODOs:

• [ ] Add sky130_scl Cadence standard cell library option @elamdf
• [x] Documentation for this alternate method
• [x] Sky130 documentation for selecting library
• [x] e2e tests

Related PRs / Issues

Type of change:

• [ ] Bug fix
• [X] New feature
• [X] Other enhancement

Impact:

• [X] Change to core Hammer
• [X] Change to a Hammer plugin
• [ ] Other

Contributor Checklist:

• [X] Did you set master as the base branch?
• [X] Did you state the type-of-change/impact?
• [X] Did you delete any extraneous prints/debugging code?
• [ ] (If applicable) Did you add documentation for the feature?
• [ ] (If applicable) Did you update the poetry.lock file if you updated the requirements in pyproject.toml?
• [ ] (If applicable) Did you add a unit test demonstrating the PR?
• [ ] (If applicable) Did you run this through the e2e integration tests?
• [ ] (If applicable) Did you update the submodules in e2e/ if this feature depends on updated plugins?

[elamdf]

syn/par works on commercial tutorial flow

[elamdf]

make tutorial=sky130-commercial power-syn BINARY=/tools/C/elamdf/chipyard_dev/tests/symmetric.riscv works as well (with joules)