ENH: autobuild/app.py needs to be able to handle multiple deprecated RPCs

[walkjivefly]

autobuild/app.py reads manifest.json and autobuild/configs/thing.base.j2 to build wallet and xbridge config fragments.

One of the things it can handle is deprecated RPCs. But the current implementation supports only 1; if

"deprecatedrpc": true

it includes a wallet fragment saying

deprecatedrpc=signrawtransaction

But, there are different deprecated RPCs for different wallets now. For example, SYS v4.2.0 has

deprecatedrpc=addresses

because

rpc: deprecate addresses and reqSigs from rpc outputs #20286.
The following RPC calls are affected: gettxout, getrawtransaction, decoderawtransaction, decodescript, gettransaction, and REST endpoints: /rest/tx, /rest/getutxos, /rest/block.

Two fields, addresses and reqSigs, are removed from the output of the above commands. 

And new sane field address is added.
Adding -deprecatedrpc=addresses to startup argument will leave reqSigs and addresses intact

Handling this needs additional code in wallet.conf.j2 but this alone will not cope with the case where a coin has multiple possible deprecatedrpc parameters. In this case only the first will be handled.