Remove DisjointSet constructor taking splatted elements

[oxinabox]

This closes #570
I can't work out how to do this without a breaking change.
I also can't workout how to deprecate the old behavior.

Normal julia collections do not allow construction with passing the iterator elements in.
That is why we have Tuple((1,2,3)) and tuple(1,2,3).

julia> Set(1, 2, 3)
ERROR: MethodError: no method matching Set(::Int64, ::Int64, ::Int64)
Closest candidates are:
  Set(::Any) at set.jl:21
Stacktrace:
 [1] top-level scope at REPL[1]:1

julia> Set((1, 2, 3))
Set([2, 3, 1])

[oxinabox]

There is one way I can think of deprecating it.
We deprecate the whole DisjointSets type in favour of a new DisjointSet type.
#579

[codecov]

Codecov Report

Merging #578 into master will increase coverage by 7.07%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master     #578      +/-   ##
==========================================
+ Coverage   87.96%   95.03%   +7.07%     
==========================================
  Files          33       33              
  Lines        2110     2819     +709     
==========================================
+ Hits         1856     2679     +823     
+ Misses        254      140     -114

Impacted Files	Coverage Δ
src/disjoint_set.jl	98.52% <ø> (+4.18%)	⬆️
src/DataStructures.jl	100% <ø> (ø)	⬆️
src/balanced_tree.jl	96.19% <0%> (-1.44%)	⬇️
src/heaps/binary_heap.jl	100% <0%> (ø)	⬆️
src/dict_support.jl	100% <0%> (ø)	⬆️
src/list.jl	100% <0%> (ø)	⬆️
src/int_set.jl	100% <0%> (ø)	⬆️
src/fenwick.jl	100% <0%> (ø)	⬆️
src/circular_buffer.jl	100% <0%> (ø)	⬆️
... and 22 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 3b66dbc...ede791d. Read the comment docs.