Rework CI to run tests locally using the VM-installed Postgres on all
target platforms.
### CI jobs
* Build release versions on Linux/Win/Mac and save build results as
output artifacts
* In a separate VMs (Linux/Win/Mac)
* use
[nyurik/action-setup-postgis](https://github.com/nyurik/action-setup-postgis)
to install postgis and run tests using the built artifacts
* run `cargo test` on Linux only
* copy built artifacts from the build step, and run tests using the
release martin binary
* package and publish if this is a release
### Other changes
* Port some minor changes from the rewrite to porting easier
* minor cleanups
* remove all "expected" data files - too unstable to be usable
* Add justfile to simplify running all the tests
* Save all PBF outputs to the text files
* Consolidate all tests to reuse the same code
* Consolidate database initialization
* updated readme with the new instructions
Note that while this PR creates "expected" files, the CI cannot validate
the generated results because the output is not stable. Eventually we
may try to output just the non-geometry values to have reasonable tests
comparing against the expected results.
