Update navbar - Githubissues

Mimic navbar of main website: https://vespawatch.be/

[x] Set <nav class="navbar navbar-expand-lg navbar-light bg-light">
[x] The map button should have active on the homepage
[x] Set any button to btn-outline-dark rather than btn-outline-light
[x] Set d-md-inline-flex not d-lg-inline-flex on the export button, so it appears on slightly smaller screens
[x] Change <a href="/vespa-db/" class="navbar-brand">VespaDB</a> to:

<a class="navbar-brand d-flex align-items-center" href="/">
   <img class="me-3" src="/assets/images/logo.png" alt="Vespa-Watch">
   Vespa-Watch
</a>

[x] Add the logo to /assets (or wherever static files are kept)
[x] Update the name to Vespa-Watch
[x] Link to / (won't work on the test site, but will on a nesten.vespawatch.be domain
[x] Add the following sass: https://github.com/peterdesmet/petridish/blob/efb9a64438086376f9f36dd8df6cd93caefa9aa9/_sass/_navbar.scss#L3C1-L12C4 (lines 14-27 are currently not used and could be omitted)

The results should look like this:

VespaDB

inbo / vespa-db