Use of Simple MessageFormat alternative in ICU implementation in ICU4J

ICU4J implementation code uses com.ibm.icu.text.MessageFormat to generate formatted text from localized pattern text in several places. MessageFormat is dragging a lot of dependencies, therefore, it is a major blocker for ICU4J moduralization. In most cases, we need simple text replacement of patterns such as `{0} {1}`. We should have a simple message format function to do this task internally instead of using full spec MessageFormat.

This ticket was created for tracking this enhancement for ICU4J. For ICU4C, we track this enhancement by ticket #7457.