feat: add genesis command suite (gnolang#1252)

## Description

This PR introduces the genesis.json command suite, as outlined in gnolang#1203.

Closes gnolang#1203 and gnolang#1189

<details><summary>Contributors' checklist...</summary>

- [x] Added new tests, or not needed, or not feasible
- [x] Provided an example (e.g. screenshot) to aid review or the PR is
self-explanatory
- [x] Updated the official documentation or not needed
- [x] No breaking changes were made, or a `BREAKING CHANGE: xxx` message
was included in the description
- [x] Added references to related issues and PRs
- [ ] Provided any useful hints for running manual tests
- [ ] Added new benchmarks to [generated
graphs](https://gnoland.github.io/benchmarks), if any. More info
[here](https://github.com/gnolang/gno/blob/master/.benchmarks/README.md).
</details>

gno.land/Makefile

@@ -9,22 +9,24 @@ rundep=go run -modfile ../misc/devdeps/go.mod
 gnoland.start:; go run ./cmd/gnoland start
 
 .PHONY: build
-build: build.gnoland build.gnokey build.gnoweb build.gnofaucet build.gnotxsync
+build: build.gnoland build.gnokey build.gnoweb build.gnofaucet build.gnotxsync build.genesis
 
 build.gnoland:;    go build -o build/gnoland   ./cmd/gnoland
 build.gnoweb:;     go build -o build/gnoweb    ./cmd/gnoweb
 build.gnofaucet:;  go build -o build/gnofaucet ./cmd/gnofaucet
 build.gnokey:;     go build -o build/gnokey    ./cmd/gnokey
 build.gnotxsync:;  go build -o build/gnotxsync  ./cmd/gnotxsync
+build.genesis:;  go build -o build/genesis  ./cmd/genesis
 
 .PHONY: install
-install: install.gnoland install.gnoweb install.gnofaucet install.gnokey install.gnotxsync
+install: install.gnoland install.gnoweb install.gnofaucet install.gnokey install.gnotxsync install.genesis
 
 install.gnoland:;    go install ./cmd/gnoland
 install.gnoweb:;     go install ./cmd/gnoweb
 install.gnofaucet:;  go install ./cmd/gnofaucet
 install.gnokey:;     go install ./cmd/gnokey
 install.gnotxsync:;  go install ./cmd/gnotxsync
+install.genesis:;  go install ./cmd/genesis
 
 .PHONY: fclean
 fclean: clean

gno.land/cmd/genesis/balances.go

@@ -0,0 +1,39 @@
+package main
+
+import (
+	"flag"
+
+	"github.com/gnolang/gno/tm2/pkg/commands"
+)
+
+type balancesCfg struct {
+	commonCfg
+}
+
+// newBalancesCmd creates the genesis balances subcommand
+func newBalancesCmd(io *commands.IO) *commands.Command {
+	cfg := &balancesCfg{}
+
+	cmd := commands.NewCommand(
+		commands.Metadata{
+			Name:       "balances",
+			ShortUsage: "balances <subcommand> [flags]",
+			LongHelp:   "Manipulates the initial genesis.json account balances (pre-mines)",
+			ShortHelp:  "Manages genesis.json account balances",
+		},
+		cfg,
+		commands.HelpExec,
+	)
+
+	cmd.AddSubCommands(
+		newBalancesAddCmd(cfg, io),
+		newBalancesRemoveCmd(cfg, io),
+		newBalancesExportCmd(cfg, io),
+	)
+
+	return cmd
+}
+
+func (c *balancesCfg) RegisterFlags(fs *flag.FlagSet) {
+	c.commonCfg.RegisterFlags(fs)
+}