Improve performance with electrum-cash

[2qx]

Currently the API creates a new network provider for each wallet,

There is the following overhead:

• Cluster connection ~4s
• Broadcasting/listing ~1s

Alter configuration to speed up usage, either by re-configuring the electrum requirements, reusing providers or limiting hosts.

[2qx]

Fixed connection timeout for regtest and lowered request timeout in PR #39