Fix RBAC setup suggestion for wrong directory

[1000TurquoisePogs]

The file docs/user-guide/mvd-configuration.md suggested users edit a file "allowedPlugins.json" within a directory
<zowe.runtimeDirectory>/components/app-server/share/zlux-app-server/deploy/...

This directory does not exist. It was a developer directory long ago.

I have updated the incorrect references to the valid folder
<zowe.workspaceDirectory>/app-server/ZLUX/pluginStorage/org.zowe.zlux.bootstrap/plugins

This is applicable for all of v2 and v3. It may be that the old directory was valid for v1, but as that is out of support now I'm not digging too deep into that.

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[github-actions]

😺 Thank you for creating this PR! To publish your content to Zowe Docs, follow these required steps.

• Add the label review: doc.
• Identify your content topic with a label. (Examples: area: apiml, area: cli, area: install and config, etc.)
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  • If adding content that needs to be removed from V3 documentation, add the V3 N/A tag.
• Select the master branch if your PR updates content that is on the live site. Select docs-staging if your PR updates content for a future release.
• Notify the Doc Squad about this PR. If you don't know whom should review your content, message the #zowe-doc Slack channel. If you know which Doc Squad writer should approve your content, add that person as a reviewer.

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[github-actions]

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[ArooshLele]

I approve of these changes.

[ArooshLele]

I approve of these changes.

[ArooshLele]

I approve of these changes.

[ArooshLele]

I approve of these changes.

[ArooshLele]

I approve of these changes.