Merge commands keys add and keys restore into a single command.

[ljoss17]

Closes: #1075

Description

This PR merged the commands keys add and keys restore into a single command keys add. In addition to this, restoring a key with mnemonic is done by passing a file containing the mnemonic instead of directly passing the mnemonic to the command input.
The command will add a new key if the flag --key-file is given with a JSON file containing the information of the key.
Or the command will restore a key if the flag --mnemonic-file is given with a file containing the mnemonic to restore the key.

Testing

Adding a key

The key file required is generated using the following command:

gaiad keys add <key_name> --output json

And copy the output to a file. The file content should have the following format:

{
  "name": "testkey",
  "type": "local",
  "address": "cosmos1tc3vcuxyyac0dmayf887t95tdg7qpyql48w7gj",
  "pubkey": "cosmospub1addwnpepqgg7ng4ycm60pdxfzdfh4hjvkwcr3da59mr8k883vsstx60ruv7kur4525u",
  "mnemonic": "[24 words mnemonic]"
}

And then run:

hermes keys add -f <file_name> <chain_id>

Restoring a key

The file required to restore a key should have the 24 mnemonic words on the same line separated by a white space. The file content should have the following format:

word1 word2 word3 ... word24

And the command can be tested the following way:

hermes add -m <mnemonic_file> <chain_id>

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PR author checklist:

• Added changelog entry, using unclog.
• [ ] Added tests: integration (for Hermes) or unit/mock tests (for modules).
• Linked to GitHub issue.
• Updated code comments and guide (e.g., guide/).

Reviewer checklist:

• Reviewed Files changed in the GitHub PR explorer.
• Manually tested (in case integration/unit/mock tests are absent).

[ljoss17]

For this PR I changed the flag used to specify the key name from --name to --key-name, to be the same as the flag used for the keys balance command, and to be more clear that it represents the name of the key.
Since I used the default flags, the flag is now -k instead of -n. This breaks the e2e setup script. I have two potential solutions for this issue :

1. Specify that the flags for the key_name argument are --name/-n instead of --key-name/-k
2. Change the e2e.sh script to take the flag -k instead of -n

Is there a solution which would be preferable ?

[romac]

1. Specify that the flags for the key_name argument are --name/-n instead of --key-name/-k
2. Change the e2e.sh script to take the flag -k instead of -n

Is there a solution which would be preferable ?

Let's do solution 2. Please make sure to document in the changelog that the name of the flag has changed, under the breaking-changes section.