Plugins: Refactor plugin download/installation (#43046)

* installer -> repo

* add semver format checking

* add plugin callbacks in test

* remove newline

* post install only scans new directories

* remove unused stuff

* everything in own package

* add missing cli params

* make grafana version part of the API

* resolve conflicts

* tidy up logger

* fix cli and tidy log statements

* rename log package

* update struct name

* fix linter issue

* fs -> filestore

* reorder imports

* alias import

* fix test

* fix test

* inline var

* revert jsonc file

* make repo dep of manager

* actually inject the thing

* accept all args for compatability checks

* accept compat from store

* pass os + arch vals

* don't inject fs

* tidy up

* tidy up

* merge with main and tidy fs storage

* fix test

* fix packages

* fix comment + field name

* update fs naming

* fixed wire

* remove unused func

* fix mocks

* fix storage test

* renaming

* fix log line

* fix test

* re-order field

* tidying

* add test for update with same version

* fix wire for CLI

* remove use of ioutil

* don't pass field

* small tidy

* ignore code scanning warn

* fix testdata link

* update lgtm code

pkg/plugins/logger/ifaces.go

@@ -0,0 +1,17 @@
+package logger
+
+// Logger is used primarily to facilitate logging/user feedback for both
+// the grafana-cli and the grafana backend when managing plugin installs
+type Logger interface {
+	Successf(format string, args ...interface{})
+	Failuref(format string, args ...interface{})
+
+	Info(args ...interface{})
+	Infof(format string, args ...interface{})
+	Debug(args ...interface{})
+	Debugf(format string, args ...interface{})
+	Warn(args ...interface{})
+	Warnf(format string, args ...interface{})
+	Error(args ...interface{})
+	Errorf(format string, args ...interface{})
+}