Move all API resources to under a single 'api' topic

[childish-sambino]

Fixes

Checklist

• I have made a material change to the repo (functionality, testing, spelling, grammar)
• I updated my branch with the master branch.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation about the functionality in the appropriate .md file
• I have added in line documentation to the code I modified

Contributing to Twilio

All third party contributors acknowledge that any contributions they provide will be made under the same open source license that the open source project is provided under.

Short description of what this PR does:

• Chops 'api:v2010:accounts' down to just 'api:core'
• Moves all API resources to under 'api'

If you have questions, please file a support ticket, or create a Github Issue in this repository.

[codecov]

Codecov Report

Merging #19 into master will increase coverage by 0.48%.
The diff coverage is 100%.

@@            Coverage Diff            @@
##           master     #19      +/-   ##
=========================================
+ Coverage   97.01%   97.5%   +0.48%     
=========================================
  Files          20      20              
  Lines         503     560      +57     
=========================================
+ Hits          488     546      +58     
+ Misses         15      14       -1

Impacted Files	Coverage Δ
src/base-commands/twilio-api-command.js	92.39% <100%> (+0.34%)	⬆️
src/hooks/init/twilio-api.js	100% <100%> (ø)	⬆️
src/services/twilio-api/index.js	100% <100%> (ø)	⬆️
src/services/twilio-api/get-topic-name.js	100% <100%> (ø)	⬆️
src/services/twilio-api/api-browser.js	100% <100%> (ø)	⬆️
src/commands/project/add.js	94.44% <0%> (+4.32%)	⬆️

---

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 3c4e3cd...8a34d5c. Read the comment docs.