✨ Provide more configurations for page headers.

[ParthBaraiya]

Description

• Adds additional configurations for HeaderStyle.
  • Added mainAxisSize, mainAxisAlignment, rightIconConfig and leftIconConfig.
• Adds additional configurations for CalendarPageHeader, MonthPageHeader, DayPageHeader and WeekPageHeader.
  • Added titleBuilder to build custom title for header.
• Deprecations:
  • deprecated backgroundColor and iconColor from CalendarPageHeader, DayPageHeader, MonthPageHeader and WeekPageHeader.
    • Solution: use headerStyle instead.
  • deprecated leftIconVisible, rightIconVisible, leftIconPadding, rightIconPadding, leftIcon and rightIcon from HeaderStyle.
    • Solution: use rightIconConfig and leftIconConfig instead.

Checklist

• The title of my PR starts with a [Conventional Commit] prefix (fix:, feat:, docs: etc).
• I have followed the [Contributor Guide] when preparing my PR.
• I have updated/added tests for ALL new/updated/fixed functionality.
• I have updated/added relevant documentation in docs and added dartdoc comments with ///.
• I have updated/added relevant examples in examples or docs.

Breaking Change?

• Yes, this PR is a breaking change.
• No, this PR is not a breaking change.

Though this PR does not have any breaking changes, it has many deprecations which will be removed in next major release. So, resolve all the deprecation ASAP.

You can follow migration guide for help.

Related Issues

None

[PRBaraiya]

LGTM!