Add-on store: Disable add-ons manager (#14853)
Part of #13985
Summary of the issue:
The add-ons manager is now redundant, and the add-on store replicates all features.
The add-ons manager should be disabled.
Description of user facing changes
add-ons manager is disabled, commands to activate the add-ons manager are replaced with activating the add-on store.
Description of development approach
Keeps script name the same so that key bindings for add-ons manager are kept for the add-on store
