Signed-off-by: David Runge <dvzrv@archlinux.org>

Remove the helix wrapper script, as it is no longer required.
Setting HELIX_RUNTIME is no longer required as hx resolves its own location in
/usr/lib/helix/hx and now automatically finds the system-wide/ readonly
/usr/lib/helix/runtime dir (so we are only using a symlink now).
Add all direct dependencies.

As no other user but root is able to fetch and build grammars below
/var/lib/helix/runtime, the default location below /usr/lib/helix/runtime is
more suitable for the compiled grammars.
Users wanting to fetch and build grammars need to use e.g.
HELIX_RUNTIME=dir/to/users/runtime /usr/lib/helix/hx --grammar <fetch|build>