Plugins: Enable plugin runtime install/uninstall capabilities (#33836)

* add uninstall flow

* add install flow

* small cleanup

* smaller-footprint solution

* cleanup + make bp start auto

* fix interface contract

* improve naming

* accept version arg

* ensure use of shared logger

* make installer a field

* add plugin decommissioning

* add basic error checking

* fix api docs

* making initialization idempotent

* add mutex

* fix comment

* fix test

* add test for decommission

* improve existing test

* add more test coverage

* more tests

* change test func to use read lock

* refactoring + adding test asserts

* improve purging old install flow

* improve dupe checking

* change log name

* skip over dupe scanned

* make test assertion more flexible

* remove trailing line

* fix pointer receiver name

* update comment

* add context to API

* add config flag

* add base http api test + fix update functionality

* simplify existing check

* clean up test

* refactor tests based on feedback

* add single quotes to errs

* use gcmp in tests + fix logo issue

* make plugin list testing more flexible

* address feedback

* fix API test

* fix linter

* undo preallocate

* Update docs/sources/administration/configuration.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* Update docs/sources/administration/configuration.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* Update docs/sources/administration/configuration.md

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>

* fix linting issue in test

* add docs placeholder

* update install notes

* Update docs/sources/plugins/marketplace.md

Co-authored-by: Marcus Olsson <marcus.olsson@hey.com>

* update access wording

* add more placeholder docs

* add link to more info

* PR feedback - improved errors, refactor, lock fix

* improve err details

* propagate plugin version errors

* don't autostart renderer

* add H1

* fix imports

Co-authored-by: achatterjee-grafana <70489351+achatterjee-grafana@users.noreply.github.com>
Co-authored-by: Marcus Olsson <marcus.olsson@hey.com>

docs/sources/administration/configuration.md

@@ -1471,6 +1471,14 @@ Enter a comma-separated list of plugin identifiers to identify plugins that are
 
 Custom install/learn more url for enterprise plugins. Defaults to https://grafana.com/grafana/plugins/.
 
+### marketplace_app_enabled
+
+> **Note:** Available in Grafana 8.0 and later versions.
+
+Available to Grafana administrators only, the plugin marketplace app is set to `false` by default. Set it to `true` to enable the app.
+
+For more information, refer to [Plugin marketplace]({{< relref "../plugins/marketplace.md" >}}).
+
 <hr>
 
 ## [plugin.grafana-image-renderer]

docs/sources/plugins/installation.md

@@ -23,6 +23,8 @@ Follow the instructions on the Install tab. You can either install the plugin wi
 
 For more information about Grafana CLI plugin commands, refer to [Plugin commands]({{< relref "../administration/cli.md#plugins-commands" >}}).
 
+As of Grafana v8.0, Marketplace for Grafana was introduced in order to make managing plugins easier. For more information, refer to [Plugin marketplace]({{< relref "./marketplace.md" >}}).
+
 ### Install a packaged plugin
 
 After the user has downloaded the archive containing the plugin assets, they can install it by extracting the archive into their plugin directory.

docs/sources/plugins/marketplace.md

@@ -0,0 +1,22 @@
++++
+title = "Plugin marketplace"
+aliases = ["/docs/grafana/latest/plugins/marketplace/"]
+weight = 1
++++
+
+# Plugin marketplace
+
+Marketplace for Grafana is a plugin bundled with Grafana versions 8.0+. It allows users to browse and manage plugins from within Grafana. Only Grafana Admins can access and use the Marketplace.
+
+[screenshot placeholder]
+
+To use the Marketplace for Grafana, you first need to enable it in the Grafana [configuration]({{< relref "../administration/configuration.md#marketplace_app_enabled" >}}).
+
+## Install a plugin from the Marketplace
+To install a plugin ...
+
+### Updating a plugin
+To update a plugin ...
+
+## Uninstall a plugin from the Marketplace
+To uninstall a plugin ...