refactor(core): Generalize binary data manager interface (no-changelog) (#7164)

Depends on: #7092 | Story:
[PAY-768](https://linear.app/n8n/issue/PAY-768)

This PR: 
- Generalizes the `IBinaryDataManager` interface.
- Adjusts `Filesystem.ts` to satisfy the interface.
- Sets up an S3 client stub to be filled in in the next PR.
- Turns `BinaryDataManager` into an injectable service.
- Adjusts the config schema and adds new validators.

Note that the PR looks large but all the main changes are in
`packages/core/src/binaryData`.

Out of scope:
- `BinaryDataManager` (now `BinaryDataService`) and `Filesystem.ts` (now
`fs.client.ts`) were slightly refactored for maintainability, but fully
overhauling them is **not** the focus of this PR, which is meant to
clear the way for the S3 implementation. Future improvements for these
two should include setting up a backwards-compatible dir structure that
makes it easier to locate binary data files to delete, removing
duplication, simplifying cloning methods, using integers for binary data
size instead of `prettyBytes()`, writing tests for existing binary data
logic, etc.

---------

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/cli/src/WebhookHelpers.ts

@@ -14,7 +14,7 @@ import stream from 'stream';
 import { promisify } from 'util';
 import formidable from 'formidable';
 
-import { BinaryDataManager, NodeExecuteFunctions } from 'n8n-core';
+import { BinaryDataService, NodeExecuteFunctions } from 'n8n-core';
 
 import type {
 	IBinaryData,
@@ -514,7 +514,7 @@ export async function executeWebhook(
 					const binaryData = (response.body as IDataObject)?.binaryData as IBinaryData;
 					if (binaryData?.id) {
 						res.header(response.headers);
-						const stream = BinaryDataManager.getInstance().getBinaryStream(binaryData.id);
+						const stream = Container.get(BinaryDataService).getAsStream(binaryData.id);
 						void pipeline(stream, res).then(() =>
 							responseCallback(null, { noWebhookResponse: true }),
 						);
@@ -734,7 +734,7 @@ export async function executeWebhook(
 								// Send the webhook response manually
 								res.setHeader('Content-Type', binaryData.mimeType);
 								if (binaryData.id) {
-									const stream = BinaryDataManager.getInstance().getBinaryStream(binaryData.id);
+									const stream = Container.get(BinaryDataService).getAsStream(binaryData.id);
 									await pipeline(stream, res);
 								} else {
 									res.end(Buffer.from(binaryData.data, BINARY_ENCODING));