Support for ISO 19115-1:2014 metadata standard

[samkraw]

Is your feature request related to a problem? Please describe.
Currently GeoNode only supports ISO 19115:2003 from the ISO metadata standards which has been withdrawn and revised by ISO 19115-1:2014 (https://www.iso.org/standard/26020.html). This means it is not possible to upload or download metadata XML files in the current standard, or for the user to edit fields that are new to this standard (e.g. spatial resolution).

Describe the solution you'd like
ISO 19115-1:2014 is implemented, allowing for the users to edit all the fields through the GUI, as well as upload and download metadata conforming to this standard.

Describe alternatives you've considered
We are looking at ways to implement this standard ourselves as dynamic fields, but this will not allow for editing though the GUI.

Additional context
This issue has come up as we want to comply with ANZLIC metadata profile which is base don the ISO 19115-1:2014 standard.
I saw some other metadata-related issues raised (e.g. #11511), though, as far as I can tell, they are not specifically related to the new ISO standard.

[giohappy]

GeoNode depends on PyCSW, which unfortunately at the moment doesn't implement ISO19115-1.
The hope is to see some movement on that side, but even the master branch doesn't show any activity on the topic...

[giohappy]

This will be supported once #12540 and #11511 will be completed.