* Use portable Python for map merge hooks, other tools (#55658)
* Add .dmm merge driver (#55699)
This is kind of a prototype. It only fully handles a few situations,
and doesn't produce particularly easy-to-read conflict markers when it
fails. I hope that it can be useful at least some of the time, can be
improved over time, and that the lessons learned can influence a future
interactive GUI conflict resolver (integrated into StrongDMM?). In the
worst case, one can fall back to the tried and true "manually re-do one
side's changes" strategy.
**Automatic use**: In `tools/hooks/`, run `Install.bat`
**Manual use**, for Git GUIs that don't run merge drivers: while a
merge is in progress, in `tools/mapmerge2/`, double-click `Resolve Map
Conflicts.bat`
This PR also removes the error-prone "Prepare Maps.bat" /
"mapmerge.bat" workflow. Those who aren't using the hooks should
instead use `Run Before Committing.bat` before committing. First-time
contributors who opened a PR without map merging can be advised to run
`I Forgot To Map Merge.bat`.
* Fix loose double-quot in tradership_faction.dmm
Co-authored-by: Tad Hardesty <tad@platymuus.com>