Make DeconvExplorer ready for the GCB

[alex-d13]

@PelzKo found a few issues after testing the app that we want to fix before the conference:

• Move user from data upload to signature exploration #60
• JS Errors when page is loaded #61
• Tooltips not working #62
• Deconvolution takes very long #63
• Clustered Signature does not work with signatures from unit test #64
• Make "Remove Unspecific" more specific #65
• Benchmark tab does not work at all #66
• Tippfehler Startseite #67

Older issues I will fix on the way:

• Crash when uploading custom signature #46

[federicomarini]

I would say we can/should also rename the main branch away from master and have it probably renamed into main - caveat, we might need to edit some CI/CD thingies?

[federicomarini]

Side thought - the README might also benefit from some form of beauty treatment.

Given that people land on the main page if they are checking the source, we should make it a little more descriptive of what is in the repo.
Best compromise: the minimal set of info about...

• what it does
• the installation
• a (minimal, representative) screenshot?