Feat: FlexJobs Scrapper added

[AKASH722]

Description

The changes made in this pull request include the creation of a FlexJobs scrapper, implementation of unit tests for the scrapper, and updates to the documentation.

Resolves: [ #881 ]

Checklist

Before submitting this pull request, kindly verify that the ensuing checkpoints have been reached.

• [x] Have you adhered to the repository's defined coding convention rules?
• [x] Have you updated the 'documentation.md' file with the method/function documentation?
• [x] Have you sent a message along with the result or response?
• [x] Have you used the try-catch technique?
• [x] Has the method/class been added to the documentation (md file)?

Screenshots

Additional Notes/Comments

I have created the flexjobs scrapper please check that out. I want Indeed website scrapper next, so should i open another issue, or work under the same as both are job scrappers

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I certify that I have carried out the relevant checks and provided the requisite screenshot for validation by submitting this pull request. I appreciate your contribution.