Add "Petitions I've Signed " View

[KevinMGranger]

As a user, I want to easily view a list of all petitions I've signed.

If this functionality is already possible, it could benefit from being more obviously presented (even if it's a link to a pre-populated search)

[petermikitsh]

Thanks for opening this issue. We've heard this feature request in the past. It's something we should provide. I have added it to our backlog.

[NathanCastle]

Resolved in #94