Improve build target names

[MaciejG604]

Fixes #2068

Instead of project_XYAZXYAX-SXYAYZYS use the name of the workspace directory to obtain:
workspace_XYAZXYAX-SXYAYZYS

E.g.

.
├── scripts
│   ├── .scala-build
│   │   └── scripts_59f2159dd5
│   └── one.sc
├── skan
│   ├── .scala-build
│   │   └── skan_88b44a2858
│   └── main.scala
└── skan.code-workspace

[tgodzik]

LGTM! This should actually be super helpful in metals.

[lwronski]

LGTM