Fix Docker build

- Change `.dockerignore` to use a blacklist for `/build` instead of whitelist.
- Add missing `SrcCommon.props` to initial `COPY`s.

.dockerignore

@@ -12,18 +12,12 @@
 appveyor.yml
 omnisharp.json
 README.md
-
-build/**
-!build/analyzers.ruleset
-!build/tgs.docker.sh
-!build/tgs.ico
-!build/tgs.png
-!build/stylecop.json
-!build/Version.props
-!build/ControlPanelVersion.props
-!build/Common.props
-!build/NugetCommon.props
-!build/uac_elevation_manifest.xml
+build/package/**
+build/coverlet.runsettings
+build/Dockerfile
+build/GenerateMigrations.sh
+build/OpenApiValidationSettings.json
+build/tgstation-server.service
 docs
 src/DMAPI
 src/Tgstation.Server.Host/ClientApp

build/Dockerfile

@@ -29,6 +29,7 @@ COPY build/Common.props Common.props
 COPY build/NugetCommon.props NugetCommon.props
 COPY build/Version.props Version.props
 COPY build/ControlPanelVersion.props ControlPanelVersion.props
+COPY build/SrcCommon.props SrcCommon.props
 
 WORKDIR /repo/src/Tgstation.Server.Host