lsp: allow nested lsp project

Its possible to set the root directory for the lsp now from the caller.
This way we can determine the root directory from a lsp plugin and
therefore enable nested projects.
1 job for nested_lsp_root in 58 minutes and 41 seconds
Status Job ID Name Coverage
  Test
failed #790190
flatpak
flatpak

00:58:41

 
Name Stage Failure
failed
flatpak Test
Running after_script
Uploading artifacts for failed job
Uploading artifacts...
WARNING: gnome-builder-git.flatpak: no matching files
WARNING: repo.tar: no matching files
.flatpak-builder/build/gnome-builder/_flatpak_build/meson-logs/meson-log.txt: found 1 matching files

WARNING: .flatpak-builder/build/gnome-builder/_flatpak_build/meson-logs/testlog.txt: no matching files
Uploading artifacts to coordinator... ok
id=790190 responseStatus=201 Created token=7yQdxyNp
ERROR: Job failed: exit code 1