Parameterized graphql endpoint and caching

[jihuang-adobe]

Description

Instead of hardcoding it in usePersistedQueries.js, graphql endpoint namespace is now part of .env.
Graphql caching can be configured in .env.

Related Issue

#95

Motivation and Context

Both customers with AEM Guides WKND installed and Adobe internal with Reference Demo installed can use the code hosted on code sandbox, simply change the graphql endpoint namespace to enable the sample hosted app to pull content from their environment.
https://experienceleague.adobe.com/landing/experience-manager/headless/developer/code/basic-react-app.html?lang=en

How Has This Been Tested?

tested locally and tested on online hosted sandbox
https://codesandbox.io/p/sandbox/wknd-react-app-forked-gfrtlf

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• I have signed the Adobe Open Source CLA.
• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.

[davidjgonzalez]

@jihuang-adobe can you take a look at these changes.

1. Changes the wknd-shared to be the default as afiak most people (outside Adobe SC) use wknd (and not RDA)
2. Changed semantics of the Cache toggle, since what youre really doing is disabling the cache w/ its addition (it caches by default). This also helps communicate that disabling is the "outlier" case. I also added a number of comments to re-emphasize disabling cache should not be done on Production.

[davidjgonzalez]

LGTM - any more changes you have @jihuang-adobe ?

[jihuang-adobe]

OMG, LGTM is good for me. Thanks