refactor: standardize command naming

This standardization makes it somewhat easier to read stacktraces as the command names are all uniform, so it will be slightly easier to scan trace output.

plugins/plugin/subcommands/install-dependencies

@@ -2,7 +2,7 @@
 set -eo pipefail
 [[ $DOKKU_TRACE ]] && set -x
 
-plugin_install_dependencies_cmd() {
+cmd-plugin-install-dependencies() {
   declare desc="calls dependencies plugin trigger via command line"
   local cmd="plugin:install-dependencies"
   if [[ $2 == "--core" ]]; then
@@ -11,4 +11,4 @@ plugin_install_dependencies_cmd() {
   plugn trigger dependencies
 }
 
-plugin_install_dependencies_cmd "$@"
+cmd-plugin-install-dependencies "$@"