Show /contributions link in navbar when p2p enabled

[h-m-m]

Why

We want to show the /contributions link in navbar when p2p enabled because it's a key part of the p2p workflow

Pre-Merge Checklist

• All new features have been described in the pull request
• Security & accessibility have been considered
• All outstanding questions and concerns have been resolved
• Any next steps that seem like good ideas have been created as issues for future discussion & implementation
• High quality tests have been added, or an explanation has been given why the features cannot be tested
• New features have been documented, and the code is understandable and well commented
• Entry added to CHANGELOG.md if appropriate

What

Screenshots of current code:

Logged out with P2P

Logged out without P2P

Logged in

How

We're adding a prop passed to Vue that indicates if P2P is on or not, and then letting Vue show or hide the button

Testing

There are some JS tests since this is mostly a JS change

Next Steps and Concerns

We talked some about rearranging these. Our concerns were:

• arranging buttons so items of higher priority or higher usefulness stand out more, which changes depending on context
• if someone logged in trying is to give instruction to someone not logged, it should be easy without the logged in person having to memorize which buttons are and are not the same for the logged out person
• having order be consistent and predictable
• understanding that most logged in users won't be spending much time if any looking at what a not logged in person sees

Because of all these concerns, we agreed to revisit how to balance them later

Accessibility

We did not do accessibility testing for this. It seems unlikely to me that it would change the accessibility from the previous code

Security

This may reveal the link URL in the JS to someone who is not logged in. That said, that URL will still have the Devise checks, so the additional insecurity is only removing obscurity.

[solebared]

Mob reviewed!