ARROW-13616: [R] Cheat Sheet Structure

[pachadotdev]

TODOs:
Convert cheat sheet to PDF and hide slide #1.

[github-actions]

https://issues.apache.org/jira/browse/ARROW-13616

[github-actions]

⚠️ Ticket has not been started in JIRA, please click 'Start Progress'.

[jonkeane]

This looks good to me! I'm happy to merge whenever

[ursabot]

Benchmark runs are scheduled for baseline = 2039eda and contender = 68d96d1. 68d96d1 is a master commit associated with this PR. Results will be available as each benchmark for each run completes.
Conbench compare runs links:
[Finished ⬇️0.0% ⬆️0.0%] ec2-t3-xlarge-us-east-2
[Finished ⬇️0.42% ⬆️0.04%] test-mac-arm
[Finished ⬇️0.0% ⬆️3.21%] ursa-i9-9960x
[Finished ⬇️0.51% ⬆️0.0%] ursa-thinkcentre-m75q
Supported benchmarks:
ec2-t3-xlarge-us-east-2: Supported benchmark langs: Python. Runs only benchmarks with cloud = True
test-mac-arm: Supported benchmark langs: C++, Python, R
ursa-i9-9960x: Supported benchmark langs: Python, R, JavaScript
ursa-thinkcentre-m75q: Supported benchmark langs: C++, Java