Crypto api fixes

[northern-64bit]

Description

Fixes in the crypto menu for the api. This involves giving many view functions default values and changing some and adding doc strings.

How has this been tested?

These changes needs to be tested since I don't have the required api keys in order to test the changes. Some tests fail and I don't have the knowledge to fix them so help would be appreciated.

Checklist:

• Update our Hugo documentation following these guidelines.
• Update our tests following these guidelines.
• Make sure you are following our CONTRIBUTING guidelines.
• If a feature was added make sure to add it to the corresponding scripts file.

Others

• I have performed a self-review of my own code.
• I have commented my code, particularly in hard-to-understand areas.
• My code passes all the checks pylint, flake8, black, ... To speed up development you should run pre-commit install.
• New and existing unit tests pass locally with my changes. You can test this locally using pytest tests/....

[minhhoang1023]

@northern-64bit about the market command, that was specific to the coin loaded, e.g. ETH. I tried out other coins and that works well.

We could replace the value with N/A to reflect the absence of data.

[minhhoang1023]

@northern-64bit Tested and working well! Very nice job on this :)

A minor thing - can we remove the long URL, and keep the short one that you have? It's very looong! 😅

[minhhoang1023]

then let's get it merged!

[minhhoang1023]

LEGOOO 🚀