Add --build-dir to specify where built files should be placed

[sticks-stuff]

Useful for me as I test things locally so
>python3 configure.py --spcomp-dir "L:\tf2server\steamapps\common\Team Fortress 2 Dedicated Server\tf\addons\sourcemod\scripting" --build-dir "L:\tf2server\steamapps\common\Team Fortress 2 Dedicated Server\tf\addons\sourcemod"

allows me to copy all built files where they should be. In a perfect world, maybe there could be some argument like --local which would only specify one sourcemod directory and then read spcomp and place built files in there? idk lol i just figured that other ppl might find this two line change useful

[nosoop]

Not sure I can take this one in — the underlying build tool (ninja) creates a few files in the build directory, so I think having multiple projects pointing towards a server shared build directory would cause issues when switching between them.

Maybe the contrib/autoupload tooling should be improved / integrated into your workflow instead? All it does is invoke commands, so if you wanted to do something locally, having it run mv ${in} %(destpath)s/${out} (Linux) / cmd /c ${in} %(destpath)s/${out} (Windows) would work.

Alternatively we could implement a post-build local copy within configure.py, but I still feel like that's more in the scope of contrib/ (whether it's an existing tool or a new one).