Enhanced Not Found Page

[g-saracca]

What this PR does / why we need it:

Enhance the not found page.
It adds a page for when the route is not found by the router and another one for when a file, dataset or collection is not found.
It replace the existing Not Found Page alert.

Which issue(s) this PR closes:

• Closes Enhanced Not Found Page #621

Suggestions on how to test this:

Step 1: Run the Development Environment

1. Execute npm i.
2. Navigate with cd packages/design-system && npm i && npm run build.
3. Return with cd ../../.
4. Ensure you have a .env file similar to .env.example, with the variable VITE_DATAVERSE_BACKEND_URL=http://localhost:8000.
5. Navigate with cd dev-env.
6. Start the environment using ./run-env.sh unstable.
7. To verify the environment, visit http://localhost:8000 and check your local Dataverse installation.

Step 2: Test the feature

1. Create a collection, a dataset and a file.
2. Navigate to that collection and change the collection alias in the url to one that does not exist, reload page, you should see now the Not Found Page with the 'Collection' word in bold.
3. Navigate to the dataset page and modify the persistentId query param to one that does not exist, reload page, you should see now the Not Found Page with the 'Dataset' word in bold.
4. Navigate to the file page and modify the id query param to one that does not exist, reload page, you should see now the Not Found Page with the 'File' word in bold.
5. Finally type a not existing url within the spa app, like 'localhost:8000/spa/foo', you should see now the default Not Found Page with the 'Page' word in bold.

Does this PR introduce a user interface change? If mockups are available, please link/include them here:

[coveralls]

coverage: 97.713% (-0.4%) from 98.075%
when pulling a468501 on feat/621-enhance-not-found-page
into b9f3906 on develop.

[g-saracca]

@ChengShi-1 , this one also ready for review.

[ChengShi-1]

Good. I don't see any problem after inspecting code and playing the page around.

@g-saracca There is one merge conflict, could you resolve it? Thanks!

[g-saracca]

Thanks @ChengShi-1 , conflicts solved

[ChengShi-1]

Great

[ofahimIQSS]

Looks good from my end: