feat(config-api): save asset on server based on the service list provided

[pujavs]

At present config-api asset endpoint requires the exact path to which the asset is to be uploaded.
Change is that based on the service provided the asset should be saved in the respective /otp/jans/jetty/{service}/custom/ folder.

Related issue and discussion

• Parent issue: Asset Endpoint Main Requirement 2419
• Discussion chat [thread] (https://chat.gluu.org/group/service_config_api?msg=rYXXDq4ihP92W67Ng) and (https://chat.gluu.org/group/service_admin_ui?msg=2pQpLnd8zhtm6Bvji)

Logic regarding the asset-type and the directory where asset is uploaded on jetty-server:

• Client to send the list of services where the asset needs to be uploaded on jetty-server
• Service name provided by client needs to be exact as on the server
• If more than one service is provided, API will upload the same asset to all the services
• Restart of the service after upload is out of scope of API endpoint
• Base directory where the asset will be uploaded will be /opt/jans/jetty/<service-name>/custom
• Mapping of assets type and directory under /opt/jans/jetty/<service-name>/custom is as follows

Directory	Asset Type	Description
/opt/jans/jetty/<service-name>/custom/i18n	properties	Resource bundle file
/opt/jans/jetty/<service-name>/custom/libs	lib	java archive library
/opt/jans/jetty/<service-name>/custom/pages	xhtml	Web pages
/opt/jans/jetty/<service-name>/custom/static	js, css, png, gif , jpg, jpeg	Static resources like Java-script, style-sheet and images