Backport of [ui] ACL Roles in the UI, plus Role, Policy and Token management into release/1.6.x

[hc-github-team-nomad-core]

Backport

This PR is auto-generated from #17770 to be assessed for backporting due to the inclusion of the label backport/1.6.x.

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@philrenaud
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The below text is copied from the body of the original PR.

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Tells the UI where to look for roles and how to associate them to policies and tokens

Two major parts:

• let users sign in with a role-associated token and have that role's policies' abilities adhered to
• let manager tokens CRUD roles, tokens

With these changes, end-users will now see their roles' policy rules reflected in what the UI allows them to do. Further, the Access Control section allows managers to control relevant roles, tokens, and policies via the web (previously this was only doable for Policies).

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Overview of commits

• ef7bccb

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