Issue:
feat(config): add fetch endpoint for config table

## Type of Change
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- [x] New feature

## Description
<!-- Describe your changes in detail -->
Added fetch endpoint for config table.

## Motivation and Context
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Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

If you don't have an issue, we'd recommend starting with one first so the PR
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This PR adds cached fetch to config table, for dynamically configuring application.

## How did you test it?
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Did you write an integration/unit/API test to verify the code changes?
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<img width="1300" alt="image" src="https://user-images.githubusercontent.com/43412619/215578409-3bbc50c1-47e2-46b8-86f4-23b44ac44db5.png">


## Checklist
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- [x] I formatted the code `cargo +nightly fmt --all`
- [x] I addressed lints thrown by `cargo clippy`
- [x] I reviewed submitted code


Resolution:
<think>
PR Context:
- Title: feat(cache): add generic cache functions to populate and invalidate cache
- Merged: 2023-02-03T14:05:42Z
- Files changed: 2 files
- Commits: 6 commits

Implementation approach:
## Type of Change
<!-- Put an `x` in the boxes that apply -->
- [x] Enhancement

## Description
<!-- Describe your changes in detail -->
This adds generic helper functions which helps to populate cache and update cache.

## Motivation and Context
<!--
Why is this change required? What problem does it solve?
If it fixes an open issue, please link to the issue here.

If you don't have an issue, we'd recommend starting with one first so the PR
can focus on the implementation (unless i
</think>

To implement this, you'll need to modify:


**Detailed Implementation:**


**Commit 1:** feat(cache): add generic cache functions to populate and invalidate cache (#483)
Files to modify:


**crates/router/src/db.rs**
  Add:
    - mod: pub::cache

**crates/router/src/db/cache.rs**
  Add:
    - function: pub::get_or_populate_cache
    - function: pub::redact_cache