Adding the timeout flag for fileserver command and setting default timeout to 60 seconds

[KaminFay]

Please check below, if the PR fulfills these requirements:

• Commit(s) and code follow the repositories guidelines.
• Test(s) have been added or updated to support these change(s).
• Doc(s) have been added or updated to support these change(s).

Associated Links:

• Issue: [BUG] Hauler fileserve fails on large files due to hardcoded 15 second timeout. #243
• Documentation PR: 19

Types of Changes:

• Bugfix

Proposed Changes:

• Changing the default fileserver http timeout from 15 seconds to 60 seconds to account for larger files.
• Adding an additional flag to the fileserver command to manipulate the desired timeout. This will allow end users to stipulate the timeout if they require excessively large file transfers or have a slow network connection.
• Proposed new command:

Serve the file server

Usage:
  hauler store serve fileserver [flags]

Flags:
      --directory string   Directory to use for backend.  Defaults to $PWD/fileserver (default "fileserver")
  -h, --help               help for fileserver
  -p, --port int           Port to listen on. (default 8080)
  -t, --timeout int        Set the http request timeout duration in seconds for both reads and write. (default 60)

Global Flags:
      --cache string       (deprecated flag and currently not used)
  -l, --log-level string    (default "info")
  -s, --store string       Location to create store at (default "store")

Verification/Testing of Changes:

1. Load a large file into the store.
2. Serve the fileserver with the following flag --timeout 1
3. Attempt to curl for the large file and note the immediate timeout after 1 second.
4. Close the fileserver
5. Reserve with either no flag (60 second timeout) or a large timeout --timeout 300
6. Attempt to curl for the large file and and note the download proceeds with no issues.

Additional Context:

• Edit: Opened a new PR with signed commits.
• This was a rather simple change that meets both requested ideas from the linked github issue.

1. Extends the default timeout as 15 seconds appears to be too short in some cases.
2. Allows the end user to support their needs with a variable timeout.

[zackbradys]

Thank you for your descriptive PR, code contribution, and relevant updates to the hauler-docs. LGTM!! 🚀 🚀