Here is the functionality matrix for ArcGIS Enterprise (which includes ArcGIS Server); https://www.esri.com/content/dam/esrisites/en-us/media/brochures/arcgis-enterprise-functionality-mat...
For the geodatabase licenses, this is based on the ArcGIS Server license. An Enterprise Geodatabase can be created with any level of ArcGIS Server license (Basic, Standard, Advanced). Now you will need a Standard or Advanced ArcGIS Pro client to use this tool; Create an enterprise geodatabase—Geodatabases | Documentation
What do you mean by the following?
License metrics means is it depend on cpu cores ? Or what metrics?
How about license periods(yearly, perpetual)
If I have a license for arcgis server 10.5 is it can be used to upgrade to 10.7? Or its version based?
How many geodatabase can be licensed per one ArcGIS server license?
How to know Pricing list as per Server also its extensions (Like data interoperability server?)
ArcGIS Server is licenses per core.
Depending on what you would like, I believe that there are Term and Perpetual licensing available.
If you are current on your maintenance then you should be able to upgrade to the latest version. Are the licenses avaialbe for a newer version in your My Esri account?
You can licenses as many Enterprise geodatabases on a single RDBMS with a single ArcGIS Server license.
You really should be in contact with your Esri Account manager (if in the US) or distributor on pricing and licensing questions / restrictions.
Esri Sales - https://www.esri.com/en-us/contact#c=us&t=1
Hope that helps!
Although this is focused on virtualized environments, it is useful for understanding core licensing: https://www.esri.com/content/dam/esrisites/en-us/media/whitepaper/licensing-arcgis-enterprise-deploy... (and, who isn't running in virtualized environments these days)