CRAM: Be explicit about spec IDs instead of using ordinal()

[jmthibault79]

Description

Using ordinal() is brittle because code will break mysteriously if the orders of enums ever change. These Encoding, Block Compression Method, and BlockContentType IDs are mandated by the spec.

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)

[jmthibault79]

Inspired by review comments in #1219 which cover the use of ordinal() for EncodingKey/DataSeries

[lbergelson]

@jmthibault79 Thank you, I have comment on naming and the inevitable request for more javadoc. 👍 to merge when those are addressed.

[lbergelson]

The naming of these is inconsistent and "spec" seems a bit strange in the name. I would drop spec and just go with getId or getTypeId as appropriate. The javadoc is a good addition, it would make sense to put it as class level javadoc and on the getter, as well since users will never actually see the enum constructor.

[codecov-io]

Codecov Report

Merging #1221 into master will increase coverage by 0.097%.
The diff coverage is 95.122%.

@@               Coverage Diff               @@
##              master     #1221       +/-   ##
===============================================
+ Coverage     68.879%   68.976%   +0.097%     
- Complexity      8068      8118       +50     
===============================================
  Files            540       542        +2     
  Lines          32663     32852      +189     
  Branches        5527      5566       +39     
===============================================
+ Hits           22498     22660      +162     
- Misses          7968      7994       +26     
- Partials        2197      2198        +1

Impacted Files	Coverage Δ	Complexity Δ
...sjdk/samtools/cram/structure/BlockContentType.java	100% <100%> (ø)	3 <2> (+2)	⬆️
...ava/htsjdk/samtools/cram/structure/EncodingID.java	100% <100%> (ø)	3 <2> (+2)	⬆️
...ain/java/htsjdk/samtools/cram/structure/Block.java	62.5% <100%> (ø)	30 <0> (ø)	⬇️
...amtools/cram/structure/BlockCompressionMethod.java	100% <100%> (ø)	3 <2> (+2)	⬆️
...jdk/samtools/cram/structure/CompressionHeader.java	89.441% <100%> (ø)	28 <0> (ø)	⬇️
...k/samtools/cram/encoding/ByteArrayLenEncoding.java	67.241% <50%> (ø)	5 <0> (ø)	⬇️
...k/samtools/cram/encoding/ExternalIntegerCodec.java	43.75% <0%> (-14.583%)	3% <0%> (ø)
src/main/java/htsjdk/samtools/cram/io/LTF8.java	95.181% <0%> (-0.851%)	27% <0%> (+8%)
...encoding/huffman/codec/HuffmanIntegerEncoding.java	85.714% <0%> (ø)	10% <0%> (?)
...am/encoding/huffman/codec/HuffmanByteEncoding.java	43.75% <0%> (ø)	5% <0%> (?)
... and 3 more

[lbergelson]

👍