Add B2ppK line in Hb2ppX builder

Adding additional line in renamed Hb2ppX builder (renamed from Lb2ppX) for normalisation mode in analysis of decay Lb->pp~n. Names of existing lines have been changed to have uniform names in the builder, but cuts and algorithms of existing lines are unchanged.

Lines added: Hb2ppXB2ppKLine Line name changes: Lb2ppbarLb2Charged2BodyLine -> Hb2ppXLb2ppnLine Lb2ppbarLb2Charged2BodySSLine -> Hb2ppXLb2ppnSSLine

Timing and rate info, 100,000 events 2018 year test, highest rates for the 3 years:

`| *Decision name*                                             |*Rate,%*|*Accepted*|*Mult* |*ms/evt*|
 |!StrippingHb2ppXLb2ppnLine                                   |  0.0480|        48|  1.000|   4.096|
 |!StrippingHb2ppXLb2ppnSSLine                                 |  0.0060|         6|  1.000|   0.071|
 |!StrippingHb2ppXB2ppKLine                                    |  0.0420|        42|  2.310|   0.433|
 |!StrippingHb2ppXLb2ppnLine_TIMING                            |  0.0480|        48|  1.000|   0.068|
 |!StrippingHb2ppXLb2ppnSSLine_TIMING                          |  0.0060|         6|  1.000|   0.065|
 |!StrippingHb2ppXB2ppKLine_TIMING                             |  0.0420|        42|  2.310|   0.081| <- New Line