Add Google Analytics, Dotfile, Segment and Square access-review connectors

Two OAuth2 and two API-key connectors:

- Google Analytics (GA4): OAuth2 with both analytics.readonly and
  analytics.manage.users.readonly (readonly alone 403s on the accounts
  list); v1alpha accessBindings enumerated at account and property level
  and merged by email; manual account picker (Pattern 1) with a
  per-connection probe and name resolver; distinct from Google Workspace.
- Dotfile: API key in the X-DOTFILE-API-KEY header (Pattern 3); GET
  /v1/users (owner/admin, suspended_at) with a static probe.
- Segment (Twilio): Public API token as Bearer with a required Region
  setting (US or EU) mapped to the regional host; GET /users plus per-user
  GET /users/{id} for roles and /invites for pending members; per-connection
  BuildProbeURL.
- Square: OAuth2 (EMPLOYEES_READ) or a personal access token (Pattern 3);
  POST /v2/team-members/search returns email/status/is_owner directly, so no
  role resolution; custom probe and name resolver.

Google Analytics and Square are confidential OAuth clients, wired into the
bootstrap OAuth provider list and .env.example. Segment carries a required
extra setting, so the console add-source dialog maps region onto its
segmentRegion API-key input; without that mapping the value is silently
dropped and the create is rejected.

Cassette-backed driver tests plus unit tests for the Segment probe URL and
the bootstrap OAuth provider list.

Signed-off-by: Aurélien Sibiril <81782+aureliensibiril@users.noreply.github.com>

pkg/accessreview/drivers/testdata/dotfile.yaml

@@ -0,0 +1,41 @@
+---
+# Hand-authored cassette for GET /v1/users (Dotfile, X-DOTFILE-API-KEY header,
+# stripped by the recorder). include_suspended=true returns active and suspended
+# users in one page; count=3 terminates pagination. Three synthetic users cover
+# owner/admin/member and active vs suspended (suspended_at set → inactive). The
+# User shape (id, first_name, last_name, email, role, created_at, suspended_at)
+# mirrors the documented schema.
+version: 2
+interactions:
+    - id: 0
+      request:
+        proto: HTTP/1.1
+        proto_major: 1
+        proto_minor: 1
+        content_length: 0
+        host: api.dotfile.com
+        form:
+            include_suspended:
+                - "true"
+            limit:
+                - "100"
+            page:
+                - "1"
+        headers:
+            Accept:
+                - application/json
+        url: https://api.dotfile.com/v1/users?include_suspended=true&limit=100&page=1
+        method: GET
+      response:
+        proto: HTTP/2.0
+        proto_major: 2
+        proto_minor: 0
+        content_length: -1
+        uncompressed: true
+        body: '{"data":[{"id":"a1b2c3d4-0000-4000-8000-000000000001","first_name":"Alice","last_name":"Martin","email":"alice.martin@example.com","role":"owner","created_at":"2023-01-31T13:30:00.000Z","suspended_at":null},{"id":"a1b2c3d4-0000-4000-8000-000000000002","first_name":"Bob","last_name":"Durand","email":"bob.durand@example.com","role":"admin","created_at":"2023-02-15T09:00:00.000Z","suspended_at":null},{"id":"a1b2c3d4-0000-4000-8000-000000000003","first_name":"Carla","last_name":"Petit","email":"carla.petit@example.com","role":"member","created_at":"2023-03-01T11:45:00.000Z","suspended_at":"2024-12-11T08:00:00.000Z"}],"pagination":{"page":1,"limit":100,"count":3}}'
+        headers:
+            Content-Type:
+                - application/json
+        status: 200 OK
+        code: 200
+        duration: 100ms