[PWGLF,DPG] tpcSkimsTableCreator: add columns and refactor code

[lubynets]

Enhancement:

• Added occupancy-related variables to the table with QA variables. In case of calling the processWithTrQA() function yet another workflow, o2-analysis-occ-table-producer, is required;
• Added $N\sigma_{\mathrm{ITS}}$ variable to all tables in V0 and TOF structs;
• Added occupancyMedianTime column (see PR #14202) to all tables in V0 and TOF structs.

Code cleaning and refactoring:

• Working functions (starting with run()) for cases without and with QA are merged into a single one. The process() functions are kept separate, so no subscription for unneeded (or unavailable) tables is required. The observed behavior for the user is not changed;
• In both V0 and TOF structs the output tables Standard and WithDeDxTrkQa are merged into a single one, since before they differed only by one column, TPCdEdxNorm. Now this column is filled with a proper value in case of call the processWithdEdxTrQA() function and with an arbitrary value -999 in case of call the processStandard() function;
• Repeating pieces of code factored out into functions or lambda-expressions;
• Common functions for V0 and TOF structs moved to the utilsTpcSkimsTableCreator.h;
• (Most of) magic constants replaced with meaningful constexpr variables;
• struct members are brought to order, using as a reference the PWGHF guiedlines.

Tagging @amaringarcia

[github-actions]

O2 linter results: ❌ 34 errors, ⚠️ 19 warnings, 🔕 0 disabled