Allow to apply service template to all projects

Description

Sometimes users want to apply the same integration like JIRA across all GitLab projects, currently templates are the only way to do that through the UI, but project integration templates only works for projects that have been created after it.

Proposal

Add a button to apply templates for projects created before it.

After user clicks on apply to projects button we have two options:

1. Apply the project service to all projects after a confirmation dialog
2. Select projects which you want that service applied using checkbox