View For hacktoberfest labeled repo

[avcwisesa]

Description

Added view for repos labeled Hacktoberfest. View is accessible from a dropdown in the navbar

Related Issue

#1680

Motivation and Context

Trying to tackle the linked issue (creating view for repos with some specific label). Proposing to manually maintain list of eligible labels (in this case hacktoberfest) because showing all available labels & use it similarly like language filter might make it look very crowded IMO

Sampled labels from some repos linked below

How Has This Been Tested?

Added unit tests for invalid topics usage in route

Screenshots (if appropriate):

navbar view

signed in user

unsigned in user

Sampled labels from some repos

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• [ x] My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• [ x] I have read the CONTRIBUTING document.
• [ x] I have added tests to cover my changes.
• All new and existing tests passed.

[schneems]

Thanks for working on this! I'm going to merge in and then clean up some style preferences.