cln: remove quotes from env vars

- only build remote_hsmd_socket
- multiple layers for build caching
- download git repo in separate command to prevent redownload
- fix COPY of symlink not possible
- copy the bitcoin.conf file
- add git hook to ensure no difference
Signed-off-by: Lakshya Singh <lakshay.singh1108@gmail.com>

hooks/pre-commit

@@ -0,0 +1,3 @@
+#!/usr/bin/sh
+
+cmp bitcoind/bitcoin.conf lightningd/bitcoin.conf