+ Add JSON support to "matrix" mode
~ Rename "regression mode" to "matrix", as it more accurately reflects a combination of variables
~ Replace bizzare "regression script" with a JSON file achieving basically the same thing
~ `run_designs` now clears run paths before it starts
~ `run_designs` no longer attempts to generated reports for runs that fail at startup
~ `verify_versions` no longer attempts to check the PDK if the environment variable PDK is not set
~ `scripts/config/config.py:get_config` -> `get_config_for_run` (more accurate)
~ `scripts/config/tcl.py:read_tcl_env` no longer exits unilaterally, raises an exception normally
- Remove Test #892
- Remove `Tcl` support from matrix mode: not tenable
- Remove Tcl extraction shell script
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Resolves#1458
+ Add test for JSON config files
~ Updated various `rm` execs to `file delete -force`
~ Test script now outputs to stdout as well as a log file
~ Moved post-run hook runner to `all.tcl`
~ Moved installation docs to their own subcategory
~ Fix security bug
~ Documentation all moved under `docs/source`, arranged hierarchically according to the table of contents
~ `Klayout` changed to `KLayout` in all logging messages
~ Readme rewritten to just be concise, parts of it isolated into standalone documentation
~ RTD builds no longer use conda (saves some time)
~ Fixed all broken links
