chore: deprecate FILES_REST in favour of RDM_FILES

This was deprecated in RDM records in August 2024
https://github.com/inveniosoftware/invenio-rdm-records/pull/1789/changes

We should've updated the docs at that point but it was missed

Author: carlinmack

docs/operate/customize/file-uploads/upload_limits.md

@@ -6,12 +6,12 @@ Limiting the maximum size for file uploads can be desirable for a few reasons, e
 ## Invenio Configuration
 
 `Invenio-Files-REST` provides some [configuration values](https://invenio-files-rest.readthedocs.io/en/latest/configuration.html) that are relevant for limiting file uploads.
-The most relevant ones are `FILES_REST_DEFAULT_MAX_FILE_SIZE` which limits the maximum size for *each* uploaded file (in bytes) and `FILES_REST_DEFAULT_QUOTA_SIZE` which limits the maximum overall size of *all* files uploaded per record (also in bytes).
+The most relevant ones are `RDM_FILES_DEFAULT_MAX_FILE_SIZE` which limits the maximum size for *each* uploaded file (in bytes) and `RDM_FILES_DEFAULT_QUOTA_SIZE` which limits the maximum overall size of *all* files uploaded per record (also in bytes).
 
-For instance, consider the case that the maximum file size is set to 10GiB, and the default quota is set to 30GiB.
-Then, the user can upload several files with a maximum size of 10GiB each.
-The user could upload 3 files with 10GiB each, or several smaller ones, or anything in between.
-However, the total size of all files deposited with a single record cannot exceed 30GiB.
+For instance, consider the case that the maximum file size is set to 10 GiB, and the default quota is set to 30 GiB.
+Then, the user can upload several files with a maximum size of 10 GiB each.
+The user could upload 3 files with 10 GiB each, or several smaller ones, or anything in between.
+However, the total size of all files deposited with a single record cannot exceed 30 GiB.
 
 **Note** that the Flask configuration option `MAX_CONTENT_LENGTH` is only applied for multi-part form uploads (e.g. community logos), but not for the files deposited with records.
 
@@ -22,16 +22,6 @@ Limiting the maximum size for file uploads and number of files is critical to av
 
 ### Configuration
 
-#### Frontend (Deposit Form)
-Controls how much the user interface allows users to upload which can be configured in `invenio.cfg`:
-
-```py
-APP_RDM_DEPOSIT_FORM_QUOTA = {
-    "maxFiles": 100,
-    "maxStorage": 30*10**9,
-}
-```
-
 #### Backend (File Storage & Record Quotas)
 
 Controls enforcement at the storage and API level:
@@ -43,13 +33,16 @@ RDM_FILES_DEFAULT_QUOTA_SIZE = 30 * 10**9
 
 RDM_FILES_DEFAULT_MAX_FILE_SIZE = 10 * 10**9
 """Max size per file 10 GB"""
+```
 
-# Files REST layer (bucket quota)
-FILES_REST_DEFAULT_QUOTA_SIZE = 30 * 10**9
-"""Bucket total storage 30 GB"""
+#### Frontend (Deposit Form)
+Controls how much the user interface allows users to upload which can be configured in `invenio.cfg`:
 
-FILES_REST_DEFAULT_MAX_FILE_SIZE = 10 * 10**9
-"""Bucket max file size 10 GB"""
+```py
+APP_RDM_DEPOSIT_FORM_QUOTA = {
+    "maxFiles": 100,
+    "maxStorage": RDM_FILES_DEFAULT_QUOTA_SIZE,
+}
 ```
 
 ### Quota lookup priority