Feat: add a Delete secret button

[Raphyyy]

This PR add an option to delete a secret from the store.
As the user can freely create secrets, he doesn't have any option to delete them in case of mistake.
He also doesn't have any way to update credentials. This PR bring at least a way to delete the secret and recreate it if he needs to.

As we need to remove the secret key completely, we need to perform a http DELETE on the secret/metadata/ path.
So the user need to have this policy rule :

path "secret/metadata/vaultPass/{storePath}/" {
  capabilities = ["delete"]
}

@mulbc while reviewing this one, you might not see the delete icon as I added fill="currentColor" on the svg file, the same way I added this attribute on the copy-username and copy-password icons in #64 . When those 2 PR will be merged, the icons should be all fine.