feat: added shimmer effect

[Jagpreet153]

Description

Added shimmer effect in all doctors page

Related Issues*

• Fixes [FEAT] : Adding a loading effect on all doctors page #172

## Checklist
- [x] I have forked the repo and pushed the changes according to contribution guidelines.
- [x] I have tested these changes locally.
- [x] I have tried to maintain the consistency of the code.
- [x] I have tested these changes locally.
- [x] I have updated the documentation accordingly.

[vercel]

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Name	Status	Preview	Comments	Updated (UTC)
medi-hub	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jun 4, 2024 6:35am
medi-hub-admin	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Jun 4, 2024 6:35am

[Jagpreet153]

@itsmohit097 Kindly assign this PR to me and add relevant labels .