Dedup tunables: Merge tunables with enable/disable/dont/no prefixes

[nirbhayc]

The change introduced by this PR essentially enables one to set/clear the value of any tunable of bool type, by prefixing its name with enable_ or disable_ respectively in the lrl. That is, to enable XYZ bool tunable one can add the following to the lrl:

enable_XYZ

Similarly, do disable it, add any of the following lines:

disable_XYZ
dont_XYZ
no_XYZ
noXYZ

** the other prefixes were added to have compatibility with existing tunable names.

As a side effect, this change cuts the total count of registered tunables by around 40.