Prepare 0.4.0 release - Githubissues

[x] Check for any bugs in app
[x] Fix any minor UI issues (ie. CSS)
[x] Update NEWS
[x] Update README
[x] Update DESCRIPTION with version number 0.4.0
[x] Make sure there are no errors or warnings in R CMD check on local OS
[x] Make sure R CMD check also pass on other major OS and R versions, e.g using rhub or GHA actions
[x] Make sure all notes in R CMD check can be explained briefly. Preferably there should be 0 notes.
[x] Run roxygen2::roxygenise()
[x] Run urlchecker::url_check()

Riksrevisjonen / pioneeR