Cleanup of matrix class

[rasolca]

• rename methods
  • add new snake_case methods (First matrix cleanup #1007)
  • deprecate old methods
• constructors:
  • evaluate which methods are needed
  • evaluate how to improve layout (offset and multiple tiles per block not currently supported)
  • change default layout? (Warning: current alignment of 64 even for few rows)
  • update tests
• after tridiagonal eigensolver refactoring:
  • evaluate removal of https://github.com/eth-cscs/DLA-Future/blob/master/include/dlaf/matrix/matrix.h#L35-L48
• remove .tpp files (First matrix cleanup #1007)
• ETI add other types? E.g. SizeType
• Move createMatrix helpers:
  • Move to different file (First matrix cleanup #1007)
  • rename in snake_case
  • separate tests
• Other matrix like snake_case renames:
  • matrix_ref
  • matrix_local (test)
  • panel
• Cleanup:
• remove deprecated Matrix methods
• remove deprecated Distribution methods
• After tridiagonal solver cleanup:
  • remove unused distribution extension method