Backport #870 (optional project names) to 7.4.x (#871)

Unlike most of the other backports, this code couldn't be directly
translated so it had to be re-implemented. Luckily, it is very simple.
This implementation is a bit messy and heavy handed with potential
panics, but I think it's probably fine since file names that aren't
UTF-8 aren't really supported anyway. The original implementation is a
lot cleaner though.

The test snapshots are (almost) all identical between the 7.5
implementation and this one. The sole exception is with the path in the
`snapshot_middleware::project` test, since I didn't feel like adding a
`name` parameter to `snapshot_project` in this implementation.

rojo-test/serve-test-snapshots/end_to_end__tests__serve__no_name_default_project_all.snap

@@ -0,0 +1,39 @@
+---
+source: tests/tests/serve.rs
+expression: "read_response.intern_and_redact(&mut redactions, root_id)"
+---
+instances:
+  id-2:
+    Children:
+      - id-3
+    ClassName: Folder
+    Id: id-2
+    Metadata:
+      ignoreUnknownInstances: true
+    Name: top-level
+    Parent: "00000000000000000000000000000000"
+    Properties: {}
+  id-3:
+    Children:
+      - id-4
+    ClassName: Folder
+    Id: id-3
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: second-level
+    Parent: id-2
+    Properties: {}
+  id-4:
+    Children: []
+    ClassName: IntValue
+    Id: id-4
+    Metadata:
+      ignoreUnknownInstances: true
+    Name: third-level
+    Parent: id-3
+    Properties:
+      Value:
+        Int64: 1337
+messageCursor: 0
+sessionId: id-1
+

rojo-test/serve-test-snapshots/end_to_end__tests__serve__no_name_default_project_info.snap

@@ -0,0 +1,14 @@
+---
+source: tests/tests/serve.rs
+assertion_line: 316
+expression: redactions.redacted_yaml(info)
+---
+expectedPlaceIds: ~
+gameId: ~
+placeId: ~
+projectName: top-level
+protocolVersion: 4
+rootInstanceId: id-2
+serverVersion: "[server-version]"
+sessionId: id-1
+

rojo-test/serve-test-snapshots/end_to_end__tests__serve__no_name_project_all.snap

@@ -0,0 +1,40 @@
+---
+source: tests/tests/serve.rs
+assertion_line: 338
+expression: "read_response.intern_and_redact(&mut redactions, root_id)"
+---
+instances:
+  id-2:
+    Children:
+      - id-3
+    ClassName: Folder
+    Id: id-2
+    Metadata:
+      ignoreUnknownInstances: true
+    Name: no_name_project
+    Parent: "00000000000000000000000000000000"
+    Properties: {}
+  id-3:
+    Children:
+      - id-4
+    ClassName: Folder
+    Id: id-3
+    Metadata:
+      ignoreUnknownInstances: false
+    Name: second-level
+    Parent: id-2
+    Properties: {}
+  id-4:
+    Children: []
+    ClassName: BoolValue
+    Id: id-4
+    Metadata:
+      ignoreUnknownInstances: true
+    Name: bool_value
+    Parent: id-3
+    Properties:
+      Value:
+        Bool: true
+messageCursor: 0
+sessionId: id-1
+

rojo-test/serve-test-snapshots/end_to_end__tests__serve__no_name_project_info.snap

@@ -0,0 +1,14 @@
+---
+source: tests/tests/serve.rs
+assertion_line: 335
+expression: redactions.redacted_yaml(info)
+---
+expectedPlaceIds: ~
+gameId: ~
+placeId: ~
+projectName: no_name_project
+protocolVersion: 4
+rootInstanceId: id-2
+serverVersion: "[server-version]"
+sessionId: id-1
+

rojo-test/serve-test-snapshots/end_to_end__tests__serve__no_name_top_level_project_all.snap

@@ -0,0 +1,20 @@
+---
+source: tests/tests/serve.rs
+assertion_line: 306
+expression: "read_response.intern_and_redact(&mut redactions, root_id)"
+---
+instances:
+  id-2:
+    Children: []
+    ClassName: StringValue
+    Id: id-2
+    Metadata:
+      ignoreUnknownInstances: true
+    Name: no_name_top_level_project
+    Parent: "00000000000000000000000000000000"
+    Properties:
+      Value:
+        String: "If this isn't named `no_name_top_level_project`, something went wrong!"
+messageCursor: 0
+sessionId: id-1
+

rojo-test/serve-test-snapshots/end_to_end__tests__serve__no_name_top_level_project_info.snap

@@ -0,0 +1,14 @@
+---
+source: tests/tests/serve.rs
+assertion_line: 300
+expression: redactions.redacted_yaml(info)
+---
+expectedPlaceIds: ~
+gameId: ~
+placeId: ~
+projectName: no_name_top_level_project
+protocolVersion: 4
+rootInstanceId: id-2
+serverVersion: "[server-version]"
+sessionId: id-1
+