✨ Update context api to include removeContext method

[PinPinIre]

Motivation

In issue #409 it was suggested updating the logger API to allow users to remove keys from the logger.

Changes

This PR updates the logger API to have a removeContext method that removes a key from the context object. No existing methods have been modified as part of this work.

Testing

To test this new functionality, the user must call removeContext with an existing key. A unit test has been added to test the existing addContext function and the new removeContext function.

---

I have gone over the contributing documentation.

[bits-bot]

All committers have signed the CLA.

[codecov-commenter]

Codecov Report

Merging #477 into master will decrease coverage by 0.30%.
The diff coverage is 50.00%.

@@            Coverage Diff             @@
##           master     #477      +/-   ##
==========================================
- Coverage   87.78%   87.47%   -0.31%     
==========================================
  Files          34       34              
  Lines        2112     2116       +4     
  Branches      416      416              
==========================================
- Hits         1854     1851       -3     
- Misses        258      265       +7     

Impacted Files	Coverage Δ
packages/logs/src/logs.entry.ts	50.76% <0.00%> (-1.62%)	⬇️
packages/logs/src/logger.ts	94.11% <100.00%> (+1.34%)	⬆️
packages/rum/src/rum.ts	86.15% <0.00%> (-4.62%)	⬇️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update e1ba46d...30673c6. Read the comment docs.

[bcaudan]

Thanks for this PR @PinPinIre!
I've fixed the formatting and merged it in #478