feat: Fine grained update delete RBAC w/ v3 gate

[fffinkel]

We would like to allow our engineers to use the rollback functionality while having auto-sync enabled, without granting them the ability to edit an application's sub-resource manifests. For compliance purposes, we can only deploy using a known set of manifests from a protected source, which is the git repo holding our manifests that engineers do not have access to.

Using the rollback functionality when auto-sync is enabled requires the user to disable auto-sync, which in turn requires update permissions on the application itself. We can allow this by doing the following:

p, my-user, applications, update, */*, allow

However, this will also allow engineers to edit application manifests. It follows that we would like to add a deny for the application's sub-resources, but as the RBAC documentation states, this deny is ignored.

This PR changes application resource RBAC to allow users to set separate update/delete permissions for the application itself, but still deny sub-resources. We can then do something like this:

p, my-user, applications, update, */*, allow
p, my-user, applications, update/*/Deployment/*, */*, deny

It introduces a breaking change to RBAC (see #19988), so it will have to wait until V3. To allow this functionality in V2, a config value (server.rbac.enablev3 in argocd-cm) was added that allows the user to opt in to this new behavior. I did my best to implement #19988 in the first commit, and then to add the config value gating in a following commit, so that the first commit can be cherry-picked or the second commit reverted when the V3 release is cut.

RBAC docs: https://argo-cd.readthedocs.io/en/stable/operator-manual/rbac/#fine-grained-permissions-for-updatedelete-action

Closes #20600

Checklist:

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[codecov]

Codecov Report

Attention: Patch coverage is 29.41176% with 12 lines in your changes missing coverage. Please review.

Project coverage is 55.07%. Comparing base (b9d5387) to head (f258ae5).
Report is 1 commits behind head on master.

Files with missing lines	Patch %	Lines
util/settings/settings.go	0.00%	9 Missing ⚠️
server/application/application.go	62.50%	2 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##           master   #20671      +/-   ##
==========================================
- Coverage   55.10%   55.07%   -0.04%     
==========================================
  Files         324      324              
  Lines       55262    55277      +15     
==========================================
- Hits        30452    30443       -9     
- Misses      22183    22215      +32     
+ Partials     2627     2619       -8     

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