Introduce singular capabilities for further management of individual plugins

[johnbillion]

This is a follow-up to #38652 which introduced singular capabilities for activating and deactivating individual plugins.

Singular capabilities should be added for controlling the ability to do the following:

• Edit an individual plugin.
• Delete an individual plugin.
• Update an individual plugin.

Low priority stretch goals which might end up in another follow-up ticket:

• Edit an individual file in a plugin.
• Install an individual new plugin.
• Upload an individual new plugin.

Network activation and deactivation for Multisite will be handled in a separate ticket.