templates: add genesis config presets for minimal/solochain (#5868)
# Description
Closes [#5790](https://github.com/paritytech/polkadot-sdk/issues/5790).
Useful for starting nodes based on minimal/solochain when doing
development or for testing omni node with less happy code paths. It is
reusing the presets defined for the nodes chain specs.
## Integration
Specifically useful for development/testing if generating chain-specs
for `minimal` or `solochain` runtimes from `templates` directories.
## Review Notes
Added `genesis_config_presets` modules for both minimal/solochain. I
reused the presets defined in each node `chain_spec` module
correspondingly.
### PRDOC
Not sure who uses templates, maybe node devs and runtime devs at start
of their learning journey, but happy to get some guidance on how to
write the prdoc if needed.
### Thinking out loud
I saw concerns around sharing functionality for such genesis config
presets between the template chains. I think there might be a case for
doing that, on the lines of this comment:
https://github.com/paritytech/polkadot-sdk/pull/4739#issuecomment-2157341035.
I would add that `parachains-common::genesis_config_heleper` contains a
few methods from those mentioned, but I am unsure if using it as a
dependency for templates is correct. Feels like the comment suggests
there should be a `commons` crate concerning just `templates`, which I
agree with to some degree, if we assume `cumulus` needs might be driven
in certain directions that are not relevant to `templates` and vice
versa. However I am not so certain about this, so would welcome some
thoughts, since I am seeing `parachains-common` being used already in a
few runtime implementations:
https://crates.io/crates/parachains-common/reverse_dependencies?page=3,
so might be a good candidate already for the `common` logic.
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Signed-off-by: Iulian Barbu <[email protected]>