Some updates for mesh generation (#3275)

* Some updates for mesh generation

* Fix nullspace test case

* Fix wrong dimension order

* Apply suggestions from review

* More error strings fixed

* Switch to push_back usage

* Switch to std::generate usage

* Fix capture

* Fix generation

* Revert if-else structure

* Fix up revert

* Remove spaces between includes

* Fix auto

* Fix comm equality check

* Simplifications

* Fix formatting

* Some updates for mesh generation

* Switch to push_back usage

* Switch to std::generate usage

* Fix capture

* Fix generation

* Revert if-else structure

* Fix up revert

* Remove spaces between includes

* Fix auto

* Fix comm equality check

* One dimensional refinement routine (#3314)

* Fix cmake

* Implement a one dimensional refinement routine

* Change to assert

* Switch to ghost mode by user choice

* Switch naming from 'edges' to 'cells'

* More 'edge' -> 'cell'

* Add parameter of intervals and explicit data type

* Bug fix in test

* Remove vector<bool> comment

* Capitalization of comments

* Split -> refined

* Doc string

* Fix edge confusion

* Switch to ghost mode default shared_facet

* Fix float comparison

* Fix typo

* Fix type

* Remove auto

* Add brackets for readability

* Fix bug in interval refinement test (#3331)

* Rename interval refinement test file

Pytest discovery previously ignored the interval test case, since it did not match the expected `test_` naming scheme

* Fix: implicit ghost_mode of interval mesh made explicit

* Fix: Bug for parallel interval refinement

Caused by assumption that ghost cells are refined on the process as well, which is not the case -> job of remote process that owns it

* Simplifications

* Fix formatting

* Fix author

* Fix rebase

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Co-authored-by: papel <xDNdnQoyTcrrMdWCVZft4YLqkaRWnRb@protonmail.com>
Co-authored-by: Garth N. Wells <gnw20@cam.ac.uk>