Parameterize channels in network config

[ZappaBoy]

Regarding #113

Creating a server to expose REST API I got this error:

Error: Failed to create Channel. channel name should match Regex /^[a-z][a-z0-9.-]*$/, but got _default

It seems that the underscore in _default is an unsupported symbol, so I solved renaming the default channel in default in all the project.

Also as noticed by @dviejokfs https://github.com/hyperledger-labs/hlf-operator/pull/113#issuecomment-1231823243: We should parameterized the channels in the resultant network config. The _default channel is useful for GoLang applications, but for Node.JS applications it fails.