Suggest triage/write access based on involvement history. (iree-org#1…

…5538)

Similar to how [LLVM
says](https://llvm.org/docs/DeveloperPolicy.html#obtaining-commit-access)
> We grant commit access to contributors with a track record of
submitting high quality patches.

(We could add more text to elaborate, WDYT?)

Preview: 

![image](https://github.com/openxla/iree/assets/4010439/21a68f32-5d82-4483-a9b5-1f87a4127598)

docs/website/docs/developers/general/contributing.md

@@ -111,8 +111,8 @@ Access to affiliated repositories is divided into three tiers:
 
 | Tier | Description | Team link |
 | ---- | ----------- | --------- |
-Triage | :material-check: Can be [assigned issues](https://docs.github.com/en/issues/tracking-your-work-with-issues/assigning-issues-and-pull-requests-to-other-github-users)<br>:material-check: Can apply labels to issues / PRs<br>:material-check: Can run workflows [without approval](https://docs.github.com/en/actions/managing-workflow-runs/approving-workflow-runs-from-public-forks) | [iree-triage](https://github.com/orgs/openxla/teams/iree-triage)
-Write | **Most developers should request this access**<br>:material-check: Can [merge approved pull requests](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/incorporating-changes-from-a-pull-request/merging-a-pull-request)<br>:material-check: Can create branches | [iree-write](https://github.com/orgs/openxla/teams/iree-write)
+Triage | **New project members should typically start here**<br>:material-check: Can be [assigned issues](https://docs.github.com/en/issues/tracking-your-work-with-issues/assigning-issues-and-pull-requests-to-other-github-users)<br>:material-check: Can apply labels to issues / PRs<br>:material-check: Can run workflows [without approval](https://docs.github.com/en/actions/managing-workflow-runs/approving-workflow-runs-from-public-forks) | [iree-triage](https://github.com/orgs/openxla/teams/iree-triage)
+Write | **Established project contributors should request this access**<br>:material-check: Can [merge approved pull requests](https://docs.github.com/en/pull-requests/collaborating-with-pull-requests/incorporating-changes-from-a-pull-request/merging-a-pull-request)<br>:material-check: Can create branches | [iree-write](https://github.com/orgs/openxla/teams/iree-write)
 Maintain | :material-check: Can [edit repository settings](https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features)<br>:material-check: Can push to [protected branches](https://docs.github.com/en/repositories/configuring-branches-and-merges-in-your-repository/managing-protected-branches/about-protected-branches) | [iree-maintain](https://github.com/orgs/openxla/teams/iree-maintain)
 
 All access tiers first require joining the