Fix(readAD2CPBinary): various issues with Bottom tracking parser

[lbesnard]

• the previous version of the parser could not possibly work. variable names were not always used properly
• amend the index values to read various Nortek variables to match the Nortek 2022 manual
• add unittest with bottom tracking provided by Clark Richards

[lbesnard]

linked to https://github.com/aodn/imos-toolbox/issues/791