Marks external neighbour set for recomputation

[bhourahine]

Also adds a variable to the main type to prevent DFTB+ updating the neighbourlist if it has been set externally.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 69.79%. Comparing base (22572cb) to head (7bfd505).
Report is 23 commits behind head on main.

❗ Current head 7bfd505 differs from pull request most recent head b8bc4d3. Consider uploading reports for the commit b8bc4d3 to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1319      +/-   ##
==========================================
- Coverage   70.86%   69.79%   -1.07%     
==========================================
  Files         231      227       -4     
  Lines       44203    42525    -1678     
==========================================
- Hits        31325    29681    -1644     
+ Misses      12878    12844      -34     

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[terminationshock]

The new flag here copies the logic from the already existing flag neigh%setExternally (see src/dftbp/dftb/periodic.F90).
If I understand the changes correctly, the latter can be removed completely and also the early return in updateNeighbourListAndSpecies is not required anymore, correct?
I am fine with your changes, but propose to remove the neigh%setExternally.

[bhourahine]

am fine with your changes, but propose to remove the neigh%setExternally.

We should probably discuss at the next devel meeting. Both solutions seem not to be fully blocking adjustment of the neighbour list and image coordinates after they are externally set.