Stateless integrated mode

[guggero]

Replaces #269.

I started reviewing #269 and noticed a few things that could be simplified.
Taking over the PR to speed things up and hopefully get this in with the next major LiT release that also includes lnd v0.14.0.

[guggero]

I'm seeing a weird error in the grpc-web calls (grpc-message: failed proxying s2c: rpc error: code = Internal desc = grpc: error while marshaling: failed to marshal, message is *proxy.frame, want proto.Message) so this doesn't fully work yet, will hold off on requesting reviews.

[guggero]

I found and fixed the bug. Stateless integrated mode is now working, with the super macaroon 🎉 So this is ready for full review and test.

Again, big kudos to @orbitalturtle for tackling this huge multi-part project!

[jamaljsr]

LGTM 👍
The frontend is fully functional from my testing. The only confusion I have is regarding the missing macaroon files for loop, pool, and faraday. Are these intentionally removed? How do we talk to the nodes via CLI? I tried using the admin.macaroon in my .lnd dir but that didn't work.

[guggero]

Thank you for the review, @jamaljsr!

You are totally correct, those macaroons shouldn't be deleted. Only when the wallet is initialized as stateless (which is the whole purpose of this PR). So I added a commit that checks what state the wallet is in.

[jamaljsr]

Just re-tested using commit 6700a2c but now im getting the error below.

bash-5.1# ls -al ~/.pool/regtest/
total 64
drwxr-xr-x    2 root     root          4096 Nov 18 14:05 .
drwxr-xr-x    4 root     root          4096 Nov 18 14:04 ..
-rw-------    1 root     root         32768 Nov 18 14:05 macaroons.db
-rw-------    1 root     root         32768 Nov 18 14:05 pool.db
-rw-r--r--    1 root     root           144 Nov 18 14:05 pool.macaroon

bash-5.1# pool --rpcserver=localhost:10009 --tlscertpath=/root/.lnd/tls.cert  --macaroonpath=/root/.pool/regtest/pool.macaroon accounts list
[pool] rpc error: code = Unknown desc = macaroon is not valid, returned false

bash-5.1# ls -al ~/.loop/regtest/
total 60
drwxr-xr-x    2 root     root          4096 Nov 18 14:05 .
drwxr-xr-x    4 root     root          4096 Nov 18 14:04 ..
-rw-------    1 root     root         32768 Nov 18 14:05 loop.db
-rw-r--r--    1 root     root           164 Nov 18 14:05 loop.macaroon
-rw-------    1 root     root         32768 Nov 18 14:05 macaroons.db

bash-5.1# loop --rpcserver=localhost:10009 --tlscertpath /root/.lnd/tls.cert  --macaroonpath /root/.loop/regtest/loop.macaroon terms
Loop Out
--------
rpc error: code = Unknown desc = macaroon is not valid, returned false

Loop In
------
rpc error: code = Unknown desc = macaroon is not valid, returned false
bash-5.1#

[guggero]

Thank you for testing! Oops. I know what the problem is, sorry I should've verified it myself first. Will fix tomorrow.