Electrumsv-sdk

- Bug fixes for conflicting python package versions across components (related to
chardet and requests packages).
- Added `--testnet` and `--scaling-testnet` options for `electrumsv` component.
`NOTE 2/06/2022`: The SDK is now strictly only intended for RegTest usage).
- Ensure multiple instances of the node do not conflict on the zmq port allocations.
- MacOS BigSur compatibility fixes. Uses OSAScript to launch new terminal windows.
- Remove http polling of subprocesses and instead check the exit returncode for status. This is
more reliable and works for any arbitrary plugin component.
- Fix graceful shutdown of all child processes via `signal.CTRL_C_EVENT` on windows.

- Removed verbose help text as this information is better conveyed via the online documentation.
The CLI should also now be self-describing.
- Added Dockerfiles for all components

- Add --rpchost and --rpcport optional args to the `node` command to connect to a node's RPC
API that is not on localhost:18332.

- Minor bug fixes

- Removed intermediate step of generating shell scripts and instead directly launch applications
via `Popen`.
- Now shows node logs when running in a new terminal or inline

- Added `install` command which decouples installation logic from `start` logic. This
results in faster startup times.
- General refactoring of codebase for organisation and readability.
- Added a "base" Docker image that installs all pre-requisites for running the SDK.