Add "hard reset" operation (#7263)

* Add "hard reset" operation

* Add Esti test for hard reset

* make gen

* Separate "hard reset" API from regular ("soft") reset API

The 2 APIs share almost no parameters.  While Git gets away with using the
same verb for several different "reset" operations, this is very confusing
in OpenAPI.

* [CR] Use Graveler branch utilities to hard-reset, check if dirty first

* [bug] Validate Ref type

Validation reports compile-time type errors at run-time ;-(.

* [bug] Reset to "branch~"

Was tpyoed to "branch/", which is obviously wrong.

* Move API to "experimental" and clean up Swagger leftovers

* Use "expected, actual" style in require.Equal in test

* [bug] Return created metarange ID on Commit

Caused strange failures like [this one](https://github.com/treeverse/lakeFS/actions/runs/7486726066/job/20377896805?pr=7263#step:4:7210)

api/swagger.yml

@@ -482,6 +482,7 @@ components:
         type:
           type: string
           enum: [object, common_prefix, reset]
+          description: What to reset according to path.
         path:
           type: string
         force:
@@ -3379,6 +3380,55 @@ paths:
         default:
           $ref: "#/components/responses/ServerError"
 
+  /repositories/{repository}/branches/{branch}/hard_reset:
+    parameters:
+      - in: path
+        name: repository
+        required: true
+        schema:
+          type: string
+      - in: path
+        name: branch
+        required: true
+        schema:
+          type: string
+    put:
+      tags:
+        - experimental
+      operationId: hardResetBranch
+      summary: hard reset branch
+      description:
+        Relocate branch to refer to ref.  Branch must not contain
+        uncommitted data.
+      parameters:
+        - in: query
+          name: ref
+          required: true
+          schema:
+            type: string
+          description: After reset, branch will point at this reference.
+        - in: query
+          name: force
+          required: false
+          schema:
+            type: boolean
+            default: false
+      responses:
+        204:
+          description: reset successful
+        400:
+          $ref: "#/components/responses/BadRequest"
+        401:
+          $ref: "#/components/responses/Unauthorized"
+        403:
+          $ref: "#/components/responses/Forbidden"
+        404:
+          $ref: "#/components/responses/NotFound"
+        420:
+          description: too many requests
+        default:
+          $ref: "#/components/responses/ServerError"
+
   /repositories/{repository}/branches/{branch}/revert:
     parameters:
       - in: path