cmd: limit global flags displayed on cli help output

[sreuland]

PR Checklist

PR Structure

• This PR has reasonably narrow scope (if not, break it down into smaller PRs).
• This PR avoids mixing refactoring changes with feature changes (split into two PRs
  otherwise).
• This PR's title starts with name of package that is most changed in the PR, ex.
  services/friendbot, or all or doc if the changes are broad or impact many
  packages.

Thoroughness

• This PR adds tests for the most critical parts of the new functionality or fixes.
• I've updated any docs (developer docs, .md
  files, etc... affected by this change). Take a look in the docs folder for a given service,
  like this one.

Release planning

• I've updated the relevant CHANGELOG (here for Horizon) if
  needed with deprecations, added features, breaking changes, and DB schema changes.
• I've decided if this PR requires a new major/minor version according to
  semver, or if it's mainly a patch change. The PR is targeted at the next
  release branch if it's not a patch change.

What

• Limit which global flags will display on -h cli output to when it's only relevant to the command's general roles that it may be performing 'ingestion', 'db update tool' or 'api server'.
• Don't show global flags on help output when the most specific sub-command still has child sub-commands, limit help output to just list of available sub-commands.

Why

The global flags are a fixed set of parameters and get displayed as a single large block on the console help output for any help request regardless of the level of horizon command. Since it's a fixed list, many of the global parameters tend to not be relevant to the context of command being requested by help and therefore can be somewhat mis-leading.

Closes #5022

Notes for review:

Start here, the solution overrides the cobra HelpFunc:
https://github.com/stellar/go/pull/5077/files#diff-7ad09d8c6e6a91967287e26e0343f0262ed02aa9fab85a0741cf665eeab514efR52

Some screen shots of help output from this PR on top, and current horizon on bottom.

`stellar-horizon -h`.

`stellar-horizon ingest -h`.

Screen shot of help output from this PR on left, and current horizon on right:
stellar-horizon db reingest range -h.

[aditya1702]

LGTM. Just need to resolve the merge conflicts.

[urvisavla]

The changes look great! The only thing I noticed is that horizon db reingest displays all global flags, whereas horizon db reingest -h does not. I believe horizon db reingest cannot be used on its own without specifying a range so I expected the output of horizon db reingest to same as horizon db reingest -h

[sreuland]

The changes look great! The only thing I noticed is that horizon db reingest displays all global flags, whereas horizon db reingest -h does not. I believe horizon db reingest cannot be used on its own without specifying a range so I expected the output of horizon db reingest to same as horizon db reingest -h

good catch, yeah, I think cobra is routing through a 'usage' output function there, so the hooked 'help' didn't get a chance to run, I'll look into it further to see if can capture that path, thanks!

[sreuland]

The changes look great! The only thing I noticed is that horizon db reingest displays all global flags, whereas horizon db reingest -h does not. I believe horizon db reingest cannot be used on its own without specifying a range so I expected the output of horizon db reingest to same as horizon db reingest -h

@urvisavla , fortunately, cobra allowed overriding the usage output in same way as help output, so i was able to apply the same global flags behavior in this case of usage - deca1cc