[angular-xmcloud][xmcloud-proxy] Move PERSONALIZE_SCOPE to angular SPA

[art-alexeyenko]

• This PR follows the Contribution Guide
• Changelog updated
• Upgrade guide entry added

Description / Motivation

This ensures PERSONALIZE_SCOPE is not duplicated between proxy and angular app.
Potentially to change in future - but so far the variable is used in both personalize and CDP page views - so the base SPA app is where it currently should be.

Testing Details

• Unit Test Added
• Manual Test/Other (Please elaborate)

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)

[addy-pathania]

As discussed, we should move all the personalize related env variables from proxy to SPA.

[art-alexeyenko]

@addy-pathania I'm not sure it is a good idea for timeout variables. Having to rebuild angular app when switching timeouts back and forth (during load test, for example?) would be a pain. And unlike the scope, timeouts are only used on server side.
@illiakovalenko what do you think?

[illiakovalenko]

@art-alexeyenko @addy-pathania I think that, potentially, we can leave "timeout" variables under the "proxy" since it's fully belongs to the middleware and proxy configuration. Like we did for "JSS_EDITING_SECRET"