Implement Syncback to support converting Roblox files to a Rojo project (#937)

This is a very large commit.
Consider checking the linked PR for more information.

CHANGELOG.md

@@ -31,9 +31,46 @@ Making a new release? Simply add the new header with the version and date undern
 
 ## Unreleased
 
+* A new command `rojo syncback` has been added. It can be used as `rojo syncback [path to project] --input [path to file]`. ([#937])
+ 	This command takes a Roblox file and pulls Instances out of it and places them in the correct position in the provided project.
+    Syncback is primarily controlled by the project file. Any Instances who are either referenced in the project file or a descendant
+    of one that is will be placed in an appropriate location.
+
+    In addition, a new field has been added to project files, `syncbackRules` to control how it behaves:
+
+    ```json
+    {
+        "syncbackRules": {
+            "ignoreTrees": [
+                "ServerStorage/ImportantSecrets",
+            ],
+            "ignorePaths": [
+                "src/ServerStorage/Secrets/*"
+            ],
+            "ignoreProperties": {
+                "BasePart": ["Color"]
+            },
+            "syncCurrentCamera": false,
+            "syncUnscriptable": true,
+        }
+    }
+    ```
+
+    A brief explanation of each field:
+
+    - `ignoreTrees` is a list of paths in the **roblox file** that should be ignored
+    - `ignorePaths` is a list of paths in the **file system** that should be ignored
+    - `ignoreProperties` is a list of properties that won't be synced back
+    - `syncCurrentCamera` is a toggle for whether to sync back the Workspace's CurrentCamera. Defaults to `false`.
+    - `syncUnscriptable` is a toggle for whether to sync back properties that cannot be set by the Roblox Studio plugin. Defaults to `true`.
+
+ 	If you are used to the `UpliftGames` version of this feature, there are a few notable differences:
+    - `syncUnscriptable` defaults to `true` instead of `false`
+    - `ignoreTrees` doesn't require the root of the project's name in it.
 * Fixed bugs and improved performance & UX for the script diff viewer ([#994])
 * Added support for `.jsonc` files for all JSON-related files (e.g. `.project.jsonc` and `.meta.jsonc`) to accompany JSONC support ([#1159])
 
+[#937]: https://github.com/rojo-rbx/rojo/pull/937
 [#994]: https://github.com/rojo-rbx/rojo/pull/994
 [#1159]: https://github.com/rojo-rbx/rojo/pull/1159