feat: bind config with cobra flags to override the conf

[deryrahman]

• overriding the config via flags provided by cobra
• mapping the flag with - delimiter instead of . delimiter (--project-name instead of --project.name)
• change flag names for each command that needs config overriding

TODO next (can be done in separate PR):

• bump salt version to support pflags
• rename --project to --project-name on entrypoint.sh for each plugins

[coveralls]

Pull Request Test Coverage Report for Build 2113048272

• 12 of 20 (60.0%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage decreased (-0.04%) to 74.645%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
config/loader.go	12	20	60.0%

Totals
Change from base Build 2112995892:	-0.04%
Covered Lines:	5882
Relevant Lines:	7880

---

💛 - Coveralls

[deryrahman]

@sravankorumilli by default, salt is flattening the config keys with dot . delimiter, eg in server config (config.sample.yaml), we will have serve.port serve.host etc as their flags naming. eg. ./optimus serve --serve.port=8000

Instead of dot ., it's better to have dash - delimiter, so it will be ./optimus serve --serve-port=8000

I’m proposing the changes for salt config to have ability to replace the flag name delimiter, like we have on EnvKeyReplacer

wdyt?

[deryrahman]

add feature to salt package for overriding config via flags raystack/salt#30

[deryrahman]

fix #257 and #271

[sravankorumilli]

What is the scope of this PR? Is it handled everywhere?

[sravankorumilli]

this change needs a corresponding change in the entrypoint.sh where ever it is referred when the optimus binary is upgraded in the plugins.

[deryrahman]

noted, after we bump the optimus version, we can later update the flag name in endpoint.sh for each plugins

[deryrahman]

What is the scope of this PR? Is it handled everywhere?

All command that use flags to override the config should be impacted @sravankorumilli

[deryrahman]

summarizing our discussions:

1. need to define which configs that are able to override and which are not
2. `--project` means to select the project, not to override the configs. Treat it as `kubectx`
3. action items: 
    - bump the plugins with `--project-name`
    - revisit it to provide `--project` for backward compatible or not

@ravisuhag @sravankorumilli