more changes to SAMTagUtil

[lbergelson]

• reverting the change from constants to static variables, deprecating the constants instead

Checklist

• [ ] Code compiles correctly
• [ ] New tests covering changes and new functionality
• [ ] All tests passing
• [ ] Extended the README / documentation, if necessary
• [ ] Is not backward compatible (breaks binary or source compatibility)

[codecov-io]

Codecov Report

Merging #1227 into master will decrease coverage by 0.198%. The diff coverage is 26.316%.

@@               Coverage Diff               @@
##              master     #1227       +/-   ##
===============================================
- Coverage     69.031%   68.832%   -0.198%     
+ Complexity      8077      8074        -3     
===============================================
  Files            539       539               
  Lines          32616     32617        +1     
  Branches        5510      5510               
===============================================
- Hits           22515     22451       -64     
- Misses          7894      7959       +65     
  Partials        2207      2207

Impacted Files	Coverage Δ	Complexity Δ
...c/main/java/htsjdk/samtools/sra/SRALazyRecord.java	71.591% <0%> (ø)	130 <0> (ø)	:arrow_down:
src/main/java/htsjdk/samtools/SAMTagUtil.java	0% <0%> (-98.649%)	0 <0> (-5)
...ain/java/htsjdk/samtools/cram/structure/Slice.java	44.545% <0%> (ø)	20 <0> (ø)	:arrow_down:
src/main/java/htsjdk/samtools/SAMTag.java	97.368% <100%> (+0.353%)	5 <2> (+2)	:arrow_up:
...n/java/htsjdk/samtools/cram/structure/SliceIO.java	88.889% <100%> (ø)	15 <0> (ø)	:arrow_down:
...ain/java/htsjdk/samtools/SAMBinaryTagAndValue.java	84.884% <100%> (ø)	54 <0> (ø)	:arrow_down:
...n/java/htsjdk/samtools/cram/structure/ReadTag.java	70.563% <100%> (ø)	65 <0> (ø)	:arrow_down:
...dk/samtools/SAMBinaryTagAndUnsignedArrayValue.java	69.231% <100%> (ø)	5 <0> (ø)	:arrow_down:
...va/htsjdk/samtools/cram/digest/ContentDigests.java	50.467% <50%> (ø)	9 <0> (ø)	:arrow_down:
src/main/java/htsjdk/samtools/SAMTextWriter.java	66.292% <50%> (ø)	12 <0> (ø)	:arrow_down:
... and 3 more

[lbergelson]

@cmnbroad Could you take a look at this? I just deprecated the SamTagUtil entirely and moved all the functionality to SAMTag so that we wouldn't have this weird split between them.

[lbergelson]

@pshapiro4broad @cmnbroad Thank you for the reviews!