Show map with unresolved signals when creating a new signal (backoffice)

[someren]

Describe the bug
Users who create signals in the backoffice would like access to the map with unresolved signals.
In order to check if a similar signal has already been reported.
Also, keeping the functionality "mee-melden" in mind.

To Reproduce
It is not a bug but a wish.

Expected behavior
The current map could be replaced with the map with unresolved signals.
Or it should be easily accessible to users without losing information which was added to the signal.

Format/protocol
Preferably in WMS format/protocol which is nicer than the API.

Screenshots

Desktop (please complete the following information):

• OS: Microsoft
• Browser Chrome
• Version ?

[someren]

Related to https://github.com/Signalen/product-steering/issues/43