Fix some cameCase rubocop offenses

[liaham]

There are some rubocop defenses w.r.t. to Ruby's naming conventions:

# Offense count: 3
# Configuration parameters: EnforcedStyle, AllowedPatterns, IgnoredPatterns.
# SupportedStyles: snake_case, camelCase
Naming/MethodName:
  Exclude:
    - 'app/controllers/workloads_controller.rb'
    - 'app/models/wl_national_holiday.rb'
    - 'app/models/wl_user_vacation.rb'

# Offense count: 4
# Configuration parameters: MinNameLength, AllowNamesEndingInNumbers, AllowedNames, ForbiddenNames.
# AllowedNames: at, by, db, id, in, io, ip, of, on, os, pp, to
Naming/MethodParameterName:
  Exclude:
    - 'app/helpers/workload_filters_helper.rb'

# Offense count: 8
# Configuration parameters: EnforcedStyle, AllowedIdentifiers.
# SupportedStyles: snake_case, camelCase
Naming/VariableName:
  Exclude:
    - 'app/helpers/workload_filters_helper.rb'

They could be easily changed independent of the individual coding skills.