Story: As a registered user, I would like to be able propose new Hermes queries to be added to Delphi

[bhermann]

Is your feature request related to a problem? Please describe.
It is hard to foresee all the metrics that users might find useful.
To allow the community to interact with Delphi it might also be a good idea to let them suggest new queries to be added to the crawling process.

Describe the solution you'd like
As a registered user, I would like to have a Contribute section of the application where I can propose a new Hermes query to be added to the process.
For this, I need to input a complete and concise description of the query.
Additionally, I need to supply a JAR file containing the implementation of the query.
The administrators are then informed of the request and are asked to review.
An administrator may reject my proposal with an explanation for that.
I may now reformulate or withdraw my proposal.
Administrators may also close my proposal if it is deemed to be unfit regarding the code of conduct.
If an administrator approves my proposal, my query is added to the crawling process by default.
I am informed about this approval and when the first data is available.

Describe alternatives you've considered
It might also be a good idea to let users formulate requests as text-only and let them seek other users that want to implement that.

Additional context
Suggested by @janniclas and @johannesduesing as part of the PG 2018/2019 course.