waveguide termination component

[simbilod]

Terminate dangling waveguides with heavily doped narrow taper to protect modulator, detectors, and other active electronics from stray light.

I guess this is identical to the taper components with a specific set of inputs, but it's commonly-used enough that it could get be its own component with good defaults, I will let the community decide

[codecov]

Codecov Report

Merging #964 (c614935) into master (b9ba805) will decrease coverage by 0.27%.
The diff coverage is 56.25%.

@@            Coverage Diff             @@
##           master     #964      +/-   ##
==========================================
- Coverage   74.36%   74.08%   -0.28%     
==========================================
  Files         431      433       +2     
  Lines       22032    22173     +141     
  Branches     2950     2972      +22     
==========================================
+ Hits        16383    16427      +44     
- Misses       4763     4857      +94     
- Partials      886      889       +3     

Impacted Files	Coverage Δ
gdsfactory/components/taper_cross_section.py	100.00% <ø> (ø)
gdsfactory/components/terminator.py	56.25% <56.25%> (ø)
gdsfactory/read/from_yaml.py	67.26% <0.00%> (-1.05%)	⬇️
gdsfactory/pdk.py	51.92% <0.00%> (-0.09%)	⬇️
gdsfactory/geometry/check_space.py	84.21% <0.00%> (ø)
gdsfactory/symbols.py	34.00% <0.00%> (ø)
gdsfactory/schematic_editor.py	14.76% <0.00%> (+0.19%)	⬆️
gdsfactory/circuitviz.py	16.41% <0.00%> (+0.25%)	⬆️

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[sourcery-ai]

Sourcery Code Quality Report

✅  Merging this PR will increase code quality in the affected files by 0.51%.

Quality metrics	Before	After	Change
Complexity	1.00 ⭐	1.00 ⭐	0.00
Method Length	67.00 🙂	70.33 🙂	3.33 👎
Working memory	9.92 😞	9.46 🙂	-0.46 👍
Quality	73.00% 🙂	73.51% 🙂	0.51% 👍

Other metrics	Before	After	Change
Lines	73	73	0

Changed files	Quality Before	Quality After	Quality Change
gdsfactory/components/taper_cross_section.py	73.00% 🙂	73.51% 🙂	0.51% 👍

Here are some functions in these files that still need a tune-up:

File	Function	Complexity	Length	Working Memory	Quality	Recommendation
gdsfactory/components/taper_cross_section.py	taper_cross_section	1 ⭐	102 🙂	15 😞	59.85% 🙂	Extract out complex expressions

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