fixes NC-2026 adds a `--network` option instead of separated options
Networks are now defined using a `--network` option that takes the case insensitive
name of an enum values as input : MAINNET, RINKEBY, ROPSTEN, GOERLI, DEV
These presets are a set of network-id, genesis file and boonodes list.
If the `--genesis-file` is provided with a valid JSON genesis file,
Pantheon uses it instead of the default network. An empty bootnodes list is then
the default value and network id is the chain id found in the genesis file.
`--network-id` and `--bootnodes` options can override these defaults.
You can of course also override the `--network-id` and `--bootnodes` for a
predefined known network (using `--network`).
User have no reason to set `--network` and `--genesis-file` options at the same
time that would lead to misunderstandings so we raise an error to prevent both
options to be defined at the same time on the command line.
Also fixes NC-2189 renaming --private-genesis-file to --genesis-file
Updates a lot of doc according to the options changes
Signed-off-by: Adrian Sutton <adrian.sutton@consensys.net>
