feat: make proxy independent with other services

[reliveyy]

This PR removes the waiting logic for tls.cert of lndbtc, lndltc and xud in proxy entrypoint.sh. And it runs proxy branch "proxy-first" too. It is a necessary step before we providing a native launcher because we could present the status API first to let the frontend know when to call create (after lnds got synced).

How to test?

It should not break anything. And there is no obvious new features introduced. A simple test would be just bring up proxy only and

• it should not break down
• it will auto-connect to other services when they are started

Todos

• [x] Add new SERVICES environment variable
• [x] Replace /root/config.sh with config.json
• [x] Replace /root/.xud, /root/.lndbtc and /root/.lndltc with /root/network/data/...

Reminders before merge

• [x] Switch proxy:latest branch to master
• [x] Switch mainnet proxy version to 1.2.0 (independent proxy + create/unlock apis)

[kilrau]

• [x] test that the regular linux cli setup/create still works

[reliveyy]

The SERVICES environment variable means everytime when other services changed (mode or disbaled) the proxy contianer will be recreated. And it's not acceptable (not independent). So I will replace SERVICES with $network_dir/data/config.json.

More about this services.json file inside data dir:

1. The Golang supports JSON format by default
2. It's more expressive than KV list like config.sh (So the config.sh idea is generally deprecated. We designed it because it's esay to export and import in bash script)
3. We only put necessay infomation about other services in config.json like disabled which we cannot tell from a stopped or missing container; and the mode which is needed in status API to print bitcoind/litecoind/geth as light mode not "Disabled" status.

[raladev]

Switch mainnet proxy version to 1.2.0 (independent proxy + create/unlock apis)

version will be bumped in next PR, for now i will change the proxy version to current mainnet version (without create/unlock apis).