Add semver upgrade edge generation support

[m1kola]

Please read RFC for better formatting and full scope. The excerpt below is just to indicate the scope covered by this specific issue.

Need to implement semver upgrade edge generation function as discussed in the RFC.

Semver

Semver based implementation is expected to:

• Satisfy the interface discussed above
• Return a list of successor bundles based on semver. The list will not include bundle versions outside the major version of the installed bundle. (In semver a new major version is intended to indicate breaking changes, and we don’t want to default to that behavior. Future iterations may include knobs to extend this behavior.)
• This mode will not allow downgrading.

As part of this issue we also need to make sure that ForceSemverUpgradeConstraints feature gate is respected:

The solver needs to be able to switch between upgrade constraint semantics based on rules defined above (see Fig 1).

[grokspawn]

blocked by #347

[m1kola]

Also I think #397 should happen first as it introduces the interface into codebase.