Bug 32924: Add the ability to filter agreement by logged in user

Bug 32924: Add the ability to filter agreement by logged in user

This patch adds a new filter checkbox at the top of the agreement list
"Show only mine" that will display agreements linked with the logged in
user.

Test plan:
Create several agreements, add your current logged in user to some of
them
On the agreement list view us the new checkbox to filter the agreements
and see those where you are involved in.

Signed-off-by: Pedro Amorim <pedro.amorim@ptfs-europe.com>
Signed-off-by: Victor Grousset/tuxayo <victor@tuxayo.net>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>