docs: add spam policy and saved reply

Introduces a new spam policy in CONTRIBUTING.md limiting community contributors to no more than 3 open PRs simultaneously to better manage team resources and triage efforts. Also adds a corresponding saved reply for closing excessive issues/PRs.

Author: alan-agius4

.github/SAVED_REPLIES.md

@@ -99,3 +99,13 @@ I'd like to remind everyone that **you only have reproducible installs if you us
 
 **It is your responsibility as a library consumer to use lockfiles**. No one wants to do a release with bugs but it sometimes happens, and the best we can do is to fix it as fast as possible with a new release. When you have a couple of thousand total dependencies it is only a matter of time until one of them has a bad release.
 ```
+
+## Angular CLI: Spam (v1)
+
+```
+Woah, looks like you've opened a lot of issues/PRs recently. While we appreciate contributions from the community, triaging and reviewing a large influx of content in a short time period takes time away from other ongoing projects. As a result, we're closing these issues/PRs to maintain the team's focus.
+
+Note that this is not necessarily a rejection of the goals or direction of any of these contributions in particular, so much as a reflection of the team's current capacity and priorities.
+
+You are welcome to open a smaller subset of issues/PRs in accordance with [our policy](https://github.com/angular/angular-cli/blob/main/CONTRIBUTING.md#-spam-policy) focused on the most important and impactful contributions and we will do our best to prioritize a response as soon as possible.
+```

CONTRIBUTING.md

@@ -12,7 +12,7 @@ to follow:
  - [Coding Rules](#rules)
  - [Commit Message Guidelines](#commit)
  - [Signing the CLA](#cla)
- - [Updating the Public API](#public-api)
+ - [Spam Policy](#spam-policy)
 
 ## <a name="coc"></a> Code of Conduct
 Help us keep Angular open and inclusive. Please read and follow our [Code of Conduct][coc].
@@ -289,6 +289,19 @@ changes to be accepted, the CLA must be signed. It's a quick process, we promise
 * For corporations we'll need you to
   [print, sign and one of scan+email, fax or mail the form][corporate-cla].
 
+## <a name="spam-policy"></a> Spam Policy
+
+Users who create excessive amounts of issues or PRs in a short time frame, particularly low-quality or low-value contributions, may see those contributions automatically closed without consideration.
+
+Community contributors should limit themselves to no more than 3 open PRs at a single time.
+
+### Why?
+
+Reviewing and shepherding PRs as well as managing large issue counts takes time and energy from the core team. Triaging a PR well enough to understand its goals and implementation takes a significant amount of time, regardless of whether the PR is ultimately accepted. This policy ensures the team is able to balance its limited resources across all contributors and projects.
+
+### Exceptions
+
+If you plan to undertake more significant work that you anticipate will generate many individual PRs, please reach out to the team in a Github issue first to validate that Angular will be able to support and accept your contributions.
 
 [coc]: https://github.com/angular/code-of-conduct/blob/main/CODE_OF_CONDUCT.md
 [commit-message-format]: https://docs.google.com/document/d/1QrDFcIiPjSLDn3EL15IJygNPiHORgU1_OOAqWjiDU5Y/edit#