[importer] Add new directory structure and public APIs

[Harshg999]

What changes were proposed in this pull request?

• (Please fill in changes proposed in this fix)

How was this patch tested?

• Manually

[github-actions]

⚠️ No test files modified. Please ensure that changes are properly tested. ⚠️

[github-actions]

Backend Code Coverage Report •

File	Stmts	Miss	Cover	Missing
desktop/libs/indexer/src/indexer
api3.py	393	268	31%	64, 70–71, 75–76, 80–81, 85, 92–93, 95–96, 98, 103–104, 114–115, 120, 132, 142, 162–173, 175–177, 184–185, 187–189, 196–200, 208–209, 216–218, 223, 232, 234, 241–242, 260–261, 279–281, 283–289, 291, 300–303, 305–306, 309–310, 312, 319–320, 322–324, 326–328, 330–337, 341, 345–347, 349, 356–358, 363–365, 367, 374–376, 390, 392, 399–401, 406, 411–412, 414–417, 419, 427, 429, 436–440, 442–450, 452–453, 456–458, 460–462, 471–472, 479–480, 486, 491, 493–494, 499–500, 502–505, 511–512, 518–519, 526, 531, 533–534, 539, 541–542, 550, 558, 569, 579–582, 584, 586–587, 589, 591, 595–596, 598–602, 604, 606–607, 609–612, 614–616, 618–620, 622–624, 626–627, 629, 637, 644–645, 647–654, 656, 666, 668–669, 671–673, 675, 677–678, 686, 688–696, 698–702, 704, 706, 708, 723, 725, 727, 729–732, 734, 740–741, 746–747, 749–753, 757, 771, 778–779
TOTAL	53593	26255	51%

Pytest Report

Tests	Skipped	Failures	Errors	Time
1105	106 💤	0 ❌	0 🔥	5m 55s ⏱️