Deprecate OTHER as a PL value

[lbergelson]

• Deprecate the PlatformValue OTHER since the spec advises omitting the PL field when the technology is not listed in the official ontology.
• A continuation of https://github.com/samtools/htsjdk/pull/1547 which deprecated BGI.
• Alphabetized the list of PL values and added clarifying comments to match the spec.

I kind of hate how I've formatted the new list but I'm not sure what a better way to do it is...

[codecov-commenter]

Codecov Report

Merging #1552 (6e5ff07) into master (d5f7e10) will increase coverage by 0.006%. The diff coverage is 100.000%.

@@               Coverage Diff               @@
##              master     #1552       +/-   ##
===============================================
+ Coverage     69.478%   69.484%   +0.006%     
  Complexity      8980      8980               
===============================================
  Files            606       606               
  Lines          35771     35778        +7     
  Branches        5944      5944               
===============================================
+ Hits           24853     24860        +7     
  Misses          8565      8565               
  Partials        2353      2353               

Impacted Files	Coverage Δ	Complexity Δ
.../main/java/htsjdk/samtools/SAMReadGroupRecord.java	93.976% <100.000%> (+0.555%)	48.000 <0.000> (ø)