[DOCS] Fix links to app module docs

[h5law]

Description

Following the merge of #459 the app/client/cli/doc directory has moved to app/client/doc this PR fixes the links in the README

Issue

Fixes N/A

Type of change

Please mark the relevant option(s):

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

List of changes

• Fix links to app documentation
• Change CLI to APP in links

Testing

• make develop_test
• LocalNet w/ all of the steps outlined in the README

Required Checklist

• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• 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)