[ADD] trp_external_user_analytic_lines

From https://code.launchpad.net/~therp-nl/therp-addons/6.1-trp_external_user_analytic_lines/+merge/231580

@StefanRijnhart 
>Thanks! Why are older items hidden using the 'to be invoiced' filter in l.271?
>
>In the module description, please mention the nice feature that the related project issues or tasks are >accessible from the analytic lines.
>
>(this implicitely explains that there are more dependencies to expect than you would gather if this module did >nothing else but extend on permissions on analytic lines. I still miss that apt-get style dialog in Odoo saying >'Installing this module will also install project_issue. Do you want to continue?')