PICARD-1861: Plugins doc changes after discussion

PLUGINS.md

@@ -153,11 +153,11 @@ The file MUST define the following mandatory metadata fields:
 
 | Field name     | Type   | Description                                                      |
 |----------------|--------|------------------------------------------------------------------|
-| id             | string | The plugin's unique name. Must be a valid Python package name and only consist of the characters `[a-z0-9_]` |
+| ~~id~~             | ~~string~~ | ~~The plugin's unique name. Must be a valid Python package name and only consist of the characters `[a-z0-9_]`~~ |
 | name           | table  | Table of multi-lingual display names. The keys are locale names. At least an English description is mandatory. |
-| author         | string | The plugin author                                                |
+| authors        | string[] | The plugin author                                                |
 | description    | table  | Table of multi-lingual detailed plugin descriptions. The keys are locale names. At least an English description is mandatory. Supports Markdown formatting. |
-| version        | string | Plugin version. Use semantic versioning in the format "x.y.z"    |
+| ~~version~~        | ~~string~~ | ~~Plugin version. Use semantic versioning in the format "x.y.z"~~    |
 | api            | list   | The Picard API versions supported by the plugin                  |
 | license        | string | License, should be a [SPDX license name](https://spdx.org/licenses/) and GPLv2 compatible |
 
@@ -389,6 +389,32 @@ activate the plugin. The UI must make it clear that the user is installing the
 plugin at their own risk and that the plugin can execute arbitrary code.
 
 
+### Blacklisting plugins
+TBD
+
+
+## Plugin management
+
+Picard will provide a command line interface and a options user interface to
+manage plugins.
+
+### Command line interface
+
+```
+picard plugin list
+picard plugin install https://git.sr.ht/~phw/picard-plugin-example
+picard plugin info https://git.sr.ht/~phw/picard-plugin-example
+picard plugin uninstall ...
+picard plugin enable ...
+picard plugin disable ...
+```
+
+Plugins can be referenced by repository URI or by `{uri-hash}-{last-path-part}`.
+E.g. the plugin can be referenced by
+`https://git.sr.ht/~phw/picard-plugin-example` or by
+`0c43dd9b75eebb260a83e6ac57b4128f-picard-plugin-example`.
+
+
 ## To be discussed
 
 ### Localization