software/theia: Add 'embedded-sr' option

Add embedded-sr and embedded-sr-type options:

• embedded-sr: (optional) URL of an SR to be supplied and requested automatically when instanciating Theia.
• embedded-sr-type: (optional) Software Type of the above SR, passed to the request.

The only effect these options have is to do standalone.supply(SR) and standalone.request(SR, "Embedded Instance", TYPE). Used in conjunction with the autorun option, they would allow an SR to be deployed in Theia "from the interface".