feat(unstable): Workspaces support (#20410)

This commit adds unstable workspace support. This is extremely
bare-bones and
minimal first-pass at this.

With this change `deno.json` supports specifying `workspaces` key, that
accepts a list of subdirectories. Each workspace can have its own import
map. It's required to specify a `"name"` and `"version"` properties in the
configuration file for the workspace:

```jsonc
// deno.json
{
  "workspaces": [
     "a",
     "b"
  },
  "imports": {
    "express": "npm:express@5"
   }
}
```
``` jsonc
// a/deno.json
{
  "name": "a",
  "version": "1.0.2",
  "imports": {
    "kleur": "npm:kleur"
  }
}
```
```jsonc
// b/deno.json
{
  "name": "b",
  "version": "0.51.0",
  "imports": {
    "chalk": "npm:chalk"
  }
}
```

`--unstable-workspaces` flag is required to use this feature:
```
$ deno run --unstable-workspaces mod.ts
```

---------

Co-authored-by: David Sherret <dsherret@gmail.com>

5 files changed, 21 insertions, 0 deletions

diff --git a/cli/tests/testdata/run/workspaces/nested_member/foo/bar/deno.json b/cli/tests/testdata/run/workspaces/nested_member/foo/bar/deno.json
new file mode 100644
index 000000000..d40328b36
--- /dev/null
+++ b/cli/tests/testdata/run/workspaces/nested_member/foo/bar/deno.json
@@ -0,0 +1,7 @@
+{
+  "name": "bar",
+  "version": "0.0.0",
+  "imports": {
+    "chalk": "npm:chalk"
+  }
+}
diff --git a/cli/tests/testdata/run/workspaces/nested_member/foo/bar/hello.ts b/cli/tests/testdata/run/workspaces/nested_member/foo/bar/hello.ts
new file mode 100644
index 000000000..9c1023153
--- /dev/null
+++ b/cli/tests/testdata/run/workspaces/nested_member/foo/bar/hello.ts
@@ -0,0 +1,3 @@
+import chalk from "chalk";
+
+export default chalk;
diff --git a/cli/tests/testdata/run/workspaces/nested_member/foo/deno.json b/cli/tests/testdata/run/workspaces/nested_member/foo/deno.json
new file mode 100644
index 000000000..68e053b02
--- /dev/null
+++ b/cli/tests/testdata/run/workspaces/nested_member/foo/deno.json
@@ -0,0 +1,7 @@
+{
+  "name": "qwerqwer",
+  "version": "0.0.0",
+  "imports": {
+    "~/": "./"
+  }
+}
diff --git a/cli/tests/testdata/run/workspaces/nested_member/foo/fizz/buzz.ts b/cli/tests/testdata/run/workspaces/nested_member/foo/fizz/buzz.ts
new file mode 100644
index 000000000..4e03777d1
--- /dev/null
+++ b/cli/tests/testdata/run/workspaces/nested_member/foo/fizz/buzz.ts
@@ -0,0 +1 @@
+export const buzz = "buzz from foo";
diff --git a/cli/tests/testdata/run/workspaces/nested_member/foo/mod.ts b/cli/tests/testdata/run/workspaces/nested_member/foo/mod.ts
new file mode 100644
index 000000000..b9d4d3c04
--- /dev/null
+++ b/cli/tests/testdata/run/workspaces/nested_member/foo/mod.ts
@@ -0,0 +1,3 @@
+import { buzz } from "~/fizz/buzz.ts";
+
+console.log(buzz);