[app] add self-reporting functionality

[sigrlami]

The most common concern about the underlying dataset that data is rather outdated for several reasons:

1. company doesn't exist anymore
2. company exist but stopped using Haskell, moved the codebase into other languages

and site visitors want to see the most up to date list of companies. I already address the first issue by moving dissolved companies into companies/inactive.csv file. To address second there should be more appropriate metric, currently two options available:

1. track official Github account (Gitlab, Bitbucket) and see if there is Haskell repositories with activity during the past 6 months
2. add self-reporting/confirmation functionality
3. track job listings

Based on these 3 metrics rank companies in a list and add "self-reported" label with the last date.