FINERACT-2421: Decrease code debt - Part 1

[adamsaghy]

Description

• Turn off processing (global) and options (avro-schemas) linting -> Too much noise, no added value
• Removed / reworked deprecated methods
• Reworked casting, better type-safety

Describe the changes made and why they were made. (Ignore if these details are present on the associated Apache Fineract JIRA ticket.)

Checklist

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[Aman-Mittal]

Seems ok to merge - refactoring is done to improve code quality.