Add modes for the emission profile bar plot without financial data

[lindadelacombaz]

Closes #133. Dear @maurolepore, I have enhanced the bar_plot_emission_profile() function, adding the different modes as arguments. The PR ended up being also a refactoring one for the bar_plot_emission_profile() function.

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TODO

• [x] Link related issue/PR.
• [x] Describe the goal of the PR. Avoid details that are clear in the diff.
• [x] Mark the PR as draft.
• [x] Include a unit test.
• [x] Review your own PR in "Files changed".
• [x] Ensure the PR branch is updated.
• [x] Ensure the checks pass.
• [x] Change the status from draft to ready.
• [x] Polish the PR description to reflect what it ended up doing.
• [x] Polish the PR title as you'd like others to read it from the git log.
• [x] Assign a reviewer.
• [x] Document user-facing changes in the changelog.