Permissionless Adapters

[jboetticher]

• Removes custom adapters array & GMP ID array
• Replaces adapter parameters with a single address array that accepts address(0) to address(248) as reserved for glacis (reservation domain subject to change, potentially we change it to 0xFFFF so that we don't limit ourselves)
• Added an array of adapters to the receive message parameters
• Finishes SimpleTokenAdapter for developers who don't want to use our token adapter

@gusjavaz Would be helpful if you looked this over when you get the chance (no rush as Halborn is looking through the current code still). Don't merge still if you do approve, as I'd like the Halborn folks to also take a look at the PR.

Also, coverage works again:

[jboetticher]

Should also leave uint8 if necessary and standardize to a higher bound (based off of GLACIS_RESERVED_IDS)