Split the LICENSE file up

[Badgerati]

Describe the Change

From v2.10.0 the LICENSE file for Pode was updated to include the licenses of other dependencies (mandatory or optional) for Pode.

The main LICENSE.txt should be left as just being the MIT license for Pode - this is so it's more obvious that Pode is MIT, and so that license parsers can detect the license for Pode, such as GitHub's.

The other dependency licenses should be split out and put into a /licenses folder, named as LICENSE.openapi-explorer.txt etc. The /licenses folder should be bundled in Pode packages and also released - for choco, docker, and pwsh gallery.

[Badgerati]

I've also added licenses for the following:

• highlightjs
• bootstrap
• font-awesome
• Microsoft.PowerShell.SecretManagement