OSS Support Grant: Milestone 2 - Add methods to inspect account storage

[MaxStalker]

Work in progress for #205

Description

This PR adds multiple new methods to query storage:

• getPaths - returning an object containing paths for public, private and storage domains
• getPathsWithType - same as above, but with more detailed info about Capabilities
• getStorageValue - returning value at specified storage path
• getStorageStats - used and storage capacity info

Jest helpers added:

• shallHavePath - checks that account have path on specified domain
• shallHaveStorageValue - checks that account have specific value stored

Documentation

Updated documentation:

• API reference for newly added functions
• Jest Asserts documentation

Tests

All new methods are covered with tests.

Changeset:

Changeset for new minor version is included

For contributor use:

• Targeted PR against master branch
• Linked to Github issue with discussion and accepted design OR link to spec that describes this work
• Code follows the standards mentioned here
• Updated relevant documentation
• Re-reviewed Files changed in the Github PR explorer
• Added appropriate labels

[changeset-bot]

🦋 Changeset detected

Latest commit: 1c7cda6

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@onflow/flow-js-testing	Minor

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[MaxStalker]

Closed in favor of #215 cause it need to be on this fork in order for scripts to work properly...