Adding RPC handler to touch files

[aryanjassal]

Description

This PR implements a RPC handler which touches files. Touching a file means that a file must be created if it doesn't exist, or update its access/modification timestamps to current time if it does.

Most likely Polykey#821 needs to be finished before this can be done.

Issues Fixed

• Relates to Polykey-CLI#244
• REF ENG-357

Tasks

• 1. Create a VaultsSecretsTouch RPC handler
• 2. Create files if they don't exist, update timestamps if they do
• 3. Add support for doing so for multiple vaults in a single commit
• 4. Add vaultOps.touchFile (or just do it manually in the handler)
• 5. Write tests for VaultsSecretsTouch
• 6. Write tests for vaultOps.touchFile (if it exists)

Final checklist

• Domain specific tests
• Full tests
• Updated inline-comment documentation
• Lint fixed
• Squash and rebased
• Sanity check the final build

[linear]

ENG-357 Implement `secrets touch` command

[aryanjassal]

In order to perform operations across vaults in a single commit, I will be re-using the header-content protocol developed during work on a similar issue for VaultsSecretsRemove handler.

First, a header message containing all the vault names will be sent, so a resource can be acquired for them all ahead of time. Then, each content message will perform all its actions within a single commit message in the vaults side.

[aryanjassal]

I will now work on the command from Polykey CLI

[aryanjassal]

The CI is passing for this, and the tests I performed in PKCLI are also working, so the secrets touch command seems to be working just fine. I will merge this along with the connected PR in PKCLI.