WIP: Hilbert/Banach space structures (#27401)
* change vecnorm to norm; introduce opnorm for matrix norms
* fixed vecnorm -> norm in tests for IterativeEigenolvers, complex, offsetarray
* dot,vecdot -> inner; deprecate vecdot
* add dot(x,y)=inner(x,y)
* use dot/inner instead of vecdot in test/offsetarray.jl
* replace length with length(LinearIndices(...
* const dot = inner
* norm(x,p) uses norm(xi) instead of norm(xi,p)
* update docstrings of norm and inner
* fixed isapprox for UniformScaling
* rename inner to dot
* fix norm of RowVector and some docstrings as suggested by @Sacha0
* additional test in 'VecOrMat of Vectors'
* removed a test in 'VecOrMat of Vectors'
* change vecdot for sparse matrices to dot
* added news
* fixed typo in NEWS and test in givens.jl
