Add utility to construct artificial interest fields from detected features

[Sven-248]

This PR handles #540 and introduces a new utility function features_to_interest_field that reconstructs an artificial interest field from a feature table (e.g. output of tobac feature detection).

The function places blobs at the detected feature positions and generates a corresponding field on a given template grid. Blob amplitude can be derived from a feature property and blob size can be estimated from feature area.

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[github-actions]

Linting results by Pylint:

Your code has been rated at 8.36/10 (previous run: 8.37/10, -0.01)
_{The linting score is an indicator that reflects how well your code version follows Pylint’s coding standards and quality metrics with respect to the RC_v1.6.x branch.
A decrease usually indicates your new code does not fully meet style guidelines or has potential errors.}

[codecov]

Codecov Report

❌ Patch coverage is 74.60317% with 16 lines in your changes missing coverage. Please review.
✅ Project coverage is 65.01%. Comparing base (8639ece) to head (fe49b39).

Files with missing lines	Patch %	Lines
tobac/utils/features_to_field.py	74.60%	16 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##           RC_v1.6.x     #566      +/-   ##
=============================================
+ Coverage      64.86%   65.01%   +0.14%     
=============================================
  Files             27       28       +1     
  Lines           4047     4110      +63     
=============================================
+ Hits            2625     2672      +47     
- Misses          1422     1438      +16     

Flag	Coverage Δ
unittests	65.01% <74.60%> (+0.14%)	⬆️

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