Made asset checkinbytag consistent with existingAPI

[ntbutler-nbcs]

Description

This is a non-breaking change to the newish Asset "checkinbytag" endpoint, to bring it inline with the usage/formatting of the other bytag endpoints that currently exist - using the URL path to define the asset_tag instead of passing it through as a url query.
E.g. instead of:
/hardware/checkinbytag?asset_tag=000242
The endpoint will now accept:
/hardware/bytag/000242/checkin

Both methods will work, but the URL Path method will take precedence if it is used (and the asset_tag query will be ignored if included at the same time)

Type of change

Please delete options that are not relevant.

• Bug fix (non-breaking change which fixes an issue)
• This change requires a documentation update

How Has This Been Tested?

• Test /hardware/bytag/xxxxxxxx/checkin endpoint with valid asset tag - asset checked in as expected
• Test /hardware/bytag/xxxxxxxx/checkin endpoint with invalid asset tag - asset not found as expected
• Test /hardware/bytag/xxxxxxxx/checkin endpoint with valid asset tag in both the request URL path AND as a query parameter to match the old method - asset checked in as expected
• Test /hardware/checkinbytag endpoint with valid asset tag passed as a query parameter - asset checked in as expected
• Test /hardware/checkinbytag endpoint with invalid asset tag passed as a query parameter - asset not found as expected

Test Configuration:

• PHP version: 8.0.20
• MySQL version 8.0
• Webserver version 6.0.2
• OS version Windows Server 2019

Checklist:

• I have read the Contributing documentation available here: https://snipe-it.readme.io/docs/contributing-overview
• I have formatted this PR according to the project guidelines: https://snipe-it.readme.io/docs/contributing-overview#pull-request-guidelines
• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• [] I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes

[snipe]

This looks great - sorry for the delay in getting this merged!