TilematrixSet and TilematrixIds stored in WMTS layers could cause errors on save request

[allyoucanmap]

to reproduce:

• create a new map
• add 16 WMTS topp:states layers from catalog
• save

There is a server internal error but nothing is displayed from MapStore.
Currently TilematrixSet and TilematrixIds are saved for each layer so in some cases that create a request to database with a body greater than 500000 char.
The body size is variable based on the tilematrix set provided by GeoServer.

Tested with a different GeoServer and in that case only 6 WMTS layers produced a body of 610000 char.