Allow for sorting by any of the valid sortType fields rather than just the date field

[shubham1g5]

MapActivity only seems to support the SortFieldConfig.FieldType.DATE field for sorting. This PR extend the functionality to support all the valid types.

[coveralls]

Pull Request Test Coverage Report for Build 1607

• 0 of 1 (0.0%) changed or added relevant line in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 52.723%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
library/src/main/java/io/ona/kujaku/activities/MapActivity.java	0	1	0.0%
<!--	Total:	0	1	0.0%	-->

Totals
Change from base Build 1606:	0.0%
Covered Lines:	3059
Relevant Lines:	5802

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💛 - Coveralls