refactor(build): rollup configuration files

[saikumarrs]

Description of the change

• Refactored rollup configuration files to extract common parts to a separate module.
• Added support for building "staging" SDKs (with a suffix).
• Fixed npm "clean" script to delete files recursively.
• Simplified the staging build spec file as a result of the above updates.

Auxilary updates:

• Fixed SDK URL matching logic in utils to support relative file paths.

Type of change

• Bug fix (non-breaking change that fixes an issue)
• New feature (non-breaking change that adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Related issues

N/A

Checklists

Development

• Lint rules pass locally
• The code changed/added as part of this pull request has been covered with tests
• All tests related to the changed code pass in development

Code review

• This pull request has a descriptive title and information useful to a reviewer. There may be a screenshot or screencast attached
• "Ready for review" label attached to the PR and reviewers mentioned in a comment
• Changes have been reviewed by at least one other engineer
• Issue from task tracker has a link to this pull request

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This change is 

[github-actions]

size-limit report 📦

Path	Size	Loading time (3g)	Running time (snapdragon)	Total time
Core - CDN	36.92 KB (-0.03% 🔽)	739 ms (-0.03% 🔽)	211 ms (-30.64% 🔽)	949 ms
All Integrations - CDN	666.73 KB (0%)	13.4 s (0%)	2.3 s (+10.3% 🔺)	15.6 s
Core - NPM	37.13 KB (-0.03% 🔽)	743 ms (-0.03% 🔽)	268 ms (+17.16% 🔺)	1.1 s