cleanup GUI special member functions (#1387)

cleanup GUI special member functions (#1387)

* cleanup gui special member functions

These tidy checks had a large impact:
cppcoreguidelines-prefer-member-initializer
modernize-use-default-member-init
modernize-use-equals-default

Some instances of other tidy issues were resolved:
clang-analyzer-optin.cplusplus.VirtualCall
cppcoreguidelines-special-member-functions
readability-inconsistent-declaration-parameter-name
readability-named-parameter
and others.

Overall we have 1334 fewer tidy checks on our code base, a
reduction of 15% of the total!

The user defined dtor for class SettingGroup was eliminated
by using std::vector<std::unique_ptr<VarSetting>> instead of a
QList of raw pointers.
The user defined dtor for class FilterWidget was eliminated
by using std::vector<std::unique_ptr<FilterOption>> instead of a
QList of raw pointers.