FINERACT-2357: Support principal & interest moratorium for progressive loans

[airajena]

Description

This PR adds principal and interest moratorium support to the Progressive repayment strategy. Principal grace produces interest-only installments for the configured number of periods and re-amortizes the remaining schedule. Interest grace defers interest (it is not waived), with deferred interest recognized in subsequent periods. It also fixes the progressive loan configuration mapping so interest grace is correctly passed through.

Changes

• Apply principal moratorium by setting grace-period EMIs to interest-only and re-amortizing remaining periods
• Treat interest-moratorium periods as zero-rate periods for EMI calculation while deferring interest
• Fix configuration mapping for graceOnInterestPayment
• Add unit coverage for principal/interest moratorium examples
• Add integration tests for progressive moratorium schedules

Testing

• ./gradlew :fineract-progressive-loan:spotlessApply :fineract-progressive-loan:spotbugsMain :fineract-progressive-loan:spotbugsTest :fineract-progressive-loan:checkstyleMain :fineract-progressive-loan:checkstyleTest
• ./gradlew :integration-tests:spotlessApply :integration-tests:spotbugsMain :integration-tests:spotbugsTest :integration-tests:checkstyleMain :integration-tests:checkstyleTest

Checklist

• Write the commit message as per our guidelines
• Acknowledge that PRs must be green (passing build)
• Create/update unit or integration tests
• Follow coding conventions
• Add required Swagger annotation and update API docs (N/A - no API changes)
• This PR is not a code dump

[adamsaghy]

@airajena Kindly review the failed checks!

[airajena]

@airajena Kindly review the failed checks!

Added the fixes