[Persistence] Adds `node` subcommand to CLI

Description

Adds the first step of the CLI harness for save and load E2E testing. This PR is the first of a series and will be followed by additional PRs adding the actual sub-command logic and execution.

node keyword was chosen contrary to #566 as per the Discussion in Discord.

Issue

Relates to a series of changes to address #566

Type of change

Please mark the relevant option(s):

[x] New feature, functionality or library
[ ] Bug fix
[ ] Code health or cleanup
[ ] Major breaking change
[ ] Documentation
[ ] Other

List of changes

Adds the node sub-command to the app CLI.

Testing

[x] make develop_test; if any code changes were made
[x] make test_e2e on k8s LocalNet; if any code changes were made
[x] e2e-devnet-test passes tests on DevNet; if any code was changed
[ ] Docker Compose LocalNet; if any major functionality was changed or introduced
[ ] k8s LocalNet; if any infrastructure or configuration changes were made

Required Checklist

[x] I have performed a self-review of my own code
[ ] I have commented my code, particularly in hard-to-understand areas
[ ] I have added, or updated, godoc format comments on touched members (see: tip.golang.org/doc/comment)
[ ] I have tested my changes using the available tooling
[ ] I have updated the corresponding CHANGELOG

If Applicable Checklist

[ ] I have updated the corresponding README(s); local and/or global
[ ] I have added tests that prove my fix is effective or that my feature works
[ ] I have added, or updated, mermaid.js diagrams in the corresponding README(s)
[ ] I have added, or updated, documentation and mermaid.js diagrams in shared/docs/* if I updated shared/*README(s)

pokt-network / pocket

[Persistence] Adds `node` subcommand to CLI #935