Fix CSV Data File export (Resolves #198)

[smarr]

Before this PR, we used the project name, which can contain arbitrary unsafe characters.
Though, the project slug is already safe.

So, we just use that one.

It's safe, because projects are created in recordProject() with

INSERT INTO Project (name, slug)
  VALUES ($1, regexp_replace($2, '[^0-9a-zA-Z-]', '-', 'g'))
  RETURNING *

This means, all none number and a-z characters are replaced with - and made safe.

See

ReBenchDB/src/backend/db/db.ts

Lines 496 to 509 in f84de3f

	public async recordProject(projectName: string): Promise<Project> {
	return this.recordCached(
	this.projects,
	projectName,
	{
	name: 'fetchProjectByName',
	text: this.queries.fetchProjectByName,
	values: [projectName]
	},
	{
	name: 'insertProject',
	text: `INSERT INTO Project (name, slug)
	VALUES ($1, regexp_replace($2, '[^0-9a-zA-Z-]', '-', 'g'))
	RETURNING *`,