feat: distinguish between adding and enabling plugins

[Wcdaren]

Feature request

The logic of enable/unenable and add/delete plugins in the plugins module (/plugin/list) is confusing. eg: the following two states cannot be effectively distinguished under the current interaction:

• Disable plugins (functionality is suspended and the original configuration information is retained)
• Delete plugins (delete all configuration information)

In addition, the display content of the form is relatively barren, and does not show the key information (status, creation time, etc.) very well

Describe the solution you'd like

Clarify the difference between adding and enabling plugins

1. form to show all the added plugins (including enabled and unenabled )
2. change the original enable plugin to add plugin
3. in the add plugin page, the specific plugin type is sorted by whether it has been added and the file name (so that the added plugins are placed in front)

With the above changes, it can also effectively solve the requirement of #2299 to quickly distinguish between enabled and unenabled plugins when adding plugins

Describe alternatives you've considered

A clear and concise description of any alternative solutions or features you've considered.

Additional context

[Baoyuantop]

LGTM, but currently APISIX does not support this feature, may need to modify manager-api to achieve it. But we plan to simplify this component in V3, so it's better if APISIX can support this feature.

[bzp2010]

Hi, @Wcdaren.

Confirming @baoyuantop's statement.

Thanks for the suggestion, I think it's a more intuitive way to interact, but storing plugin configurations like this requires significant changes in the Dashboard storage layer, so it's not possible to implement this feature until we improve it first. It will probably be implemented in v3.