Seminorm tvs

[mkerjean]

Motivation for this change

Describing topological vector spaces as vector spaces whose topology is induced by a family of seminorms. Adapting the Hahn-Banach theorem to topological vector spaces. This is necessary to formalise duality theory.

Checklist

• added corresponding entries in CHANGELOG_UNRELEASED.md

• added corresponding documentation in the headers

Reference: How to document

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• PRs with several commits that make sense individually and that
  all compile are preferentially merged into master.
• PRs with disorganized commits are very likely to be squash-rebased.

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